PRODRUGS OF 2,4-PYRIMIDINEDIAMINE COMPOUNDS AND THEIR USES

Abstract

The present disclosure provides prodrugs of biologically active 2,4-pyrimidinediamine compounds, compositions comprising the prodrugs, intermediates and methods for synthesizing the prodrugs and methods of using the prodrugs in a variety of applications.

Claims

1. A compound, comprising a 2,4-pyrimidinediamine moiety and a means for delivering the 2,4-pyrimidinediamine moiety in vivo.

2. The compound of claim 1 wherein the 2,4-pyrimidinediamine moiety comprises the structural formula (I): ##STR00030## and salts thereof, wherein: Y is selected from CH.sub.2, NR.sup.24, O, S, S(O) and S(O).sub.2; Z.sup.1 and Z.sup.2 are each, independently of one another, selected from CH and N; R.sup.2 is selected from (C1-C6) alkyl optionally substituted with one or more of the same or different R.sup.8 groups, (C3-C8) cycloalkyl optionally substituted with one or more of the same or different R.sup.8 groups, cyclohexyl optionally substituted with one or more of the same or different R.sup.8 groups, 3-8 membered cycloheteroalkyl optionally substituted with one or more of the same or different R.sup.8 groups, (C6-C14) aryl optionally substituted with one or more of the same or different R.sup.8 groups, phenyl optionally substituted with one or more of the same or different R.sup.8 groups and 5-15 membered heteroaryl optionally substituted with one or more of the same or different R.sup.8 groups; R.sup.5 is selected from halo, fluoro, cyano, nitro, trihalomethyl and trifluoromethyl; R.sup.8 is selected from R.sup.a, R.sup.b, R.sup.a substituted with one or more of the same or different R.sup.a or R.sup.b, OR.sup.a substituted with one or more of the same or different R.sup.a or R.sup.b, B(OR.sup.a).sub.2, B(NR.sup.cR.sup.c).sub.2, (CH.sub.2).sub.mR.sup.b, (CHR.sup.a).sub.mR.sup.b, O(CH.sub.2).sub.mR.sup.b, S(CH.sub.2).sub.mR.sup.b, OCHR.sup.aR.sup.b, OCR.sup.a(R.sup.b).sub.2, O(CHR.sup.a).sub.mR.sup.b, O (CH.sub.2).sub.mCH[(CH.sub.2).sub.mR.sup.b]R.sup.b, S(CHR.sup.a).sub.mR.sup.b, C(O)NH(CH.sub.2).sub.mR.sup.b, C(O)NH(CHR.sup.a).sub.mR.sup.b, O(CH.sub.2).sub.mC(O)NH(CH.sub.2).sub.mR.sup.b, S(CH.sub.2).sub.mC(O)NH(CH.sub.2).sub.mR.sup.b, O(CHR.sup.a).sub.mC(O)NH(CHR.sub.a).sub.mR.sup.b, S(CHR.sup.a).sub.mC(O)NH(CHR.sup.a).sub.mR.sup.b, NH(CH.sub.2).sub.mR.sup.b, NH(CHR.sup.a).sub.mR.sup.b, NH[(CH.sub.2).sub.mR.sup.b], N[(CH.sub.2).sub.mR.sup.b].sub.2, NHC(O)NH(CH.sub.2).sub.mR.sup.b, NHC(O)(CH.sub.2).sub.mCHR.sup.bR.sup.b and NH(CH.sub.2).sub.mC(O)NH(CH.sub.2).sub.mR.sup.b; R.sup.17 is selected from hydrogen, halogen, fluoro, lower alkyl and methyl or, alternatively, R.sup.17 may be taken together with R.sup.18 to form an oxo (O) group or, together with the carbon atom to which they are attached, a spirocycle containing from 3 to 7 carbon atoms; R.sup.18 is selected from hydrogen, halogen, fluoro, lower alkyl and methyl or, alternatively, R.sup.18 may be taken together with R.sup.17 to form an oxo (O) group or, together with the carbon atom to which they are attached, a spirocycle containing from 3 to 7 carbon atoms; R.sup.19 is selected from hydrogen, lower alkyl, and methyl or, alternatively, R.sup.19 may be taken together with R.sup.20 to form an oxo (O) group or, together with the carbon atom to which they are attached, a spirocycle containing from 3 to 7 carbon atoms; R.sup.20 is selected from hydrogen, lower alkyl and methyl or, alternatively, R.sup.20 may be taken together with R.sup.19 to form an oxo (O) group or, together with the carbon atom to which they are attached, a spirocycle containing from 3 to 7 carbon atoms; each R.sup.a is, independently of the others, selected from hydrogen, lower alkyl, lower cycloalkyl, cyclohexyl, (C4-C11) cycloalkylalkyl, (C6-C10) aryl, phenyl, (C7-C16) arylalkyl, benzyl, 2-6 membered heteroalkyl, 3-8 membered cycloheteroalkyl, morpholinyl, piperazinyl, homopiperazinyl, piperidinyl, 4-11 membered cycloheteroalkylalkyl, 5-10 membered heteroaryl and 6-16 membered heteroarylalkyl; each R.sup.b is a suitable group independently selected from O, OR.sup.a, (C1-C3) haloalkyloxy, S, SR.sup.a, NR.sup.a, NOR.sup.a, NR.sup.cR.sup.c, halogen, CF.sub.3, CN, NC, OCN, SCN, NO, NO.sub.2, N.sub.2, N.sub.3, S(O)R.sup.a, S(O).sub.2R.sup.a, S(O).sub.2OR.sup.a, S(O)NR.sup.cR.sup.c, S(O).sub.2NR.sup.cR.sup.c, OS(O)R.sup.a, OS(O).sub.2R.sup.a, OS(O).sub.2OR.sup.a, OS(O).sub.2NR.sup.cR.sup.c, C(O)R.sup.a, C(O)OR.sup.a, C(O)NR.sup.cR.sup.c, C(NH)NR.sup.cR.sup.c, C(NR.sup.a)NR.sup.cR.sup.c, C(NOH)R.sup.a, C(NOH)NR.sup.cR.sup.c, OC(O)R.sup.a, OC(O)OR.sup.a, OC(O)NR.sup.cR.sup.c, OC(NH)NR.sup.cR.sup.c, OC(NR.sup.a)NR.sup.cR.sup.c, [NHC(O)]R.sup.a, [NR.sup.aC(O)], R.sup.a, [NHC(O)].sub.nOR.sup.a, [NR.sup.aC(O)].sub.nOR.sup.a, [NHC(O)].sub.nNR.sup.cR.sup.c, [NR.sup.aC(O)].sub.nNR.sup.cR.sup.c, [NHC(NH)].sub.nNR.sup.cR.sup.c and [NR.sup.aC(NR.sup.a)].sub.nNR.sup.cR.sup.c; each R.sup.c is, independently of the others, selected from a protecting group and R.sup.a, or, alternatively, the two R.sup.c bonded to the same nitrogen atom are taken together with that nitrogen atom to form a 5 to 8-membered cycloheteroalkyl or heteroaryl which may optionally include one or more of the same or different additional heteroatoms and which may optionally be substituted with one or more of the same or different R.sup.a groups; R.sup.24 is selected from hydrogen and lower alkyl; each m is, independently of the others, an integer from 1 to 3; and each n is, independently of the others, an integer from 0 to 3.

3. The compound of claim 2 in which R.sup.5 is fluoro.

4. The compound of claim 2 in which R.sup.2 is a phenyl optionally substituted with one or more of the same or different R.sup.8 groups.

5. The compound of claim 4 in which R.sup.2 is 3,4,5-tri(loweralkoxy)phenyl.

6. The compound of claim 5 in which R.sup.2 is 3,4,5-(trimethoxy)phenyl.

7. The compound of claim 2 in which Y is O, Z.sup.1 is CH, Z.sup.2 is N, R.sup.17 and R.sup.18 are each methyl, and R.sup.19 and R.sup.20 are taken together to form an oxo group.

8. The compound of claim 7 in which R.sup.2 is a phenyl optionally substituted with one or more of the same or different R.sup.8 groups.

9. The compound of claim 8 in which R.sup.2 is 3,4,5-tri(loweralkoxy)phenyl.

10. The compound of claim 9 in which R.sup.2 is 3,4,5-(trimethoxy)phenyl.

11. The compound of claim 1 in which the means for delivering the 2,4-pyrimidinediamine moiety in vivo comprises a water solubilizing means.

12. The compound of claim 1 in which the means for delivering the 2,4-pyrimidinediamine moiety in vivo is cleaved by an esterase.

13. The compound of claim 1 in which the means for delivering the 2,4-pyrimidinediamine moiety in vivo cleaves chemically in the stomach.

14. The compound of claim 1 in which the means for delivering the 2,4-pyrimidinediamine moiety in vivo can be cleaved in the presence of a phosphatase.

15. The compound of claim 2 wherein the 2,4-pyrimidinediamine moiety has the structure (III): ##STR00031## including salts thereof, wherein each R.sup.30, R.sup.31 and R.sup.32 are each, independently of one another, selected from hydrogen, lower alkyl, lower alkenyl, lower alkynyl, (C6-C14) aryl, phenyl, 5-14 membered heteroaryl, (C7-C20) arylalkyl, benzyl, 7-20 membered heteroarylalkyl, OR, chloro, fluoro, bromo, cyano, nitro, C(O)R, C(O)OR, NRR, S(O).sub.2NRR, C(O)NRR, N(R)S(O).sub.2R and NC(O)OR, where each R is, independently of the others, selected from hydrogen and lower alkyl.

16. The compound of claim 15 in which each R.sup.30, R.sup.31 and R.sup.32 are each methoxy.

17. A pharmaceutical composition comprising a means for delivering a therapeutic agent effective to inhibit Syk in vivo, and a pharmaceutically acceptable carrier.

18. The pharmaceutical composition of claim 17 wherein the therapeutic agent comprises a 2,4-diaminopyrimidine moiety.

19. A method of administering to a subject a 2,4-pyrimidinediamine compound according to structural formula (IV): ##STR00032## including salts thereof, wherein Z.sup.1, Z.sup.2, R.sup.2, R.sup.5, R.sup.17, R.sup.18, R.sup.19 and R.sup.20 are as defined in claim 2 and Y.sup.2 is selected from CH.sub.2, NH, O and S, comprising administering to the subject a compound according to claim 2.

20. A method of inhibiting cell degranulation in a subject, comprising administering to the subject an amount of a compound according to claim 2 sufficient to deliver an amount of the 2,4-pyrimidinediamine moiety effective to inhibit degranulation.

21. The method of claim 20 in which the amount is sufficient to inhibit a disease selected from an allergic disease, low grade scarring, a disease associated with tissue destruction, a disease associated with tissue inflammation, inflammation and scarring.

22. A method of inhibiting an activity of a Syk kinase in a subject, comprising administering to the subject an amount of a compound according to claim 2 sufficient to deliver an amount of the 2,4-pyrimidinediamine moiety effective to inhibit the Syk kinase activity.

23. A method of treating or preventing an autoimmune disease in a subject, and/or one or more symptoms associated therewith, comprising administering to the subject an amount of a compound according to claim 1 to deliver sufficient 2,4-pyrimidinediamine moiety effective to treat or prevent the autoimmune disease.

24. The method of claim 23 in which the autoimmune disease is selected from Hashimoto's thyroiditis, autoimmune hemolytic anemia, autoimmune atrophic gastritis of pernicious anemia, autoimmune encephalomyelitis, autoimmune orchitis, Goodpasture's disease, autoimmune thrombocytopenia, sympathetic ophthalmia, myasthenia gravis, Graves' disease, primary biliary cirrhosis, chronic aggressive hepatitis, ulcerative colitis, membranous glomerulopathy, systemic lupus erythematosis, rheumatoid arthritis, Sjogren's syndrome, Reiter's syndrome, polymyositis-dermatomyositis, systemic sclerosis, polyarteritis nodosa, multiple sclerosis and bullous pemphigoid.

25. The method of claim 24 in which the amount of compound administered is effective to achieve a serum concentration of the 2,4-pyrimidinediamine moiety that is at or above the IC.sub.50 of Syk inhibition of the 2,4-pyrimidinediamine moiety, as measured in an in vitro assay.

Description

5. BRIEF DESCRIPTION OF THE FIGURES

[0062] FIGS. 1A and 1B provide schemes illustrating metabolic pathways of exemplary phosphorous-containing prodrugs;

[0063] FIG. 2 provides a scheme illustrating a metabolic pathway of an exemplary cyclic phosphate ester prodrug;

[0064] FIG. 3 illustrates an exemplary synthesis of exemplary cyclic phosphate prodrug; and

[0065] FIGS. 4-11 provide graphs illustrating various pharmacokinetic data for drug Compound 1 and/or prodrug Compound 4.

6. DETAILED DESCRIPTION

6.1 Definitions

[0066] As used herein, the following terms are intended to have the following meanings:

[0067] Alkyl by itself or as part of another substituent refers to a saturated or unsaturated branched, straight-chain or cyclic monovalent hydrocarbon radical having the stated number of carbon atoms (i.e., C1-C6 means one to six carbon atoms) that is derived by the removal of one hydrogen atom from a single carbon atom of a parent alkane, alkene or alkyne. Typical alkyl groups include, but are not limited to, methyl; ethyls such as ethanyl, ethenyl, ethynyl; propyls such as propan-1-yl, propan-2-yl, cyclopropan-1-yl, prop-1-en-1-yl, prop-1-en-2-yl, prop-2-en-1-yl, cycloprop-1-en-1-yl; cycloprop-2-en-1-yl, prop-1-yn-1-yl, prop-2-yn-1-yl, etc.; butyls such as butan-1-yl, butan-2-yl, 2-methyl-propan-1-yl, 2-methyl-propan-2-yl, cyclobutan-1-yl, but-1-en-1-yl, but-1-en-2-yl, 2-methyl-prop-1-en-1-yl, but-2-en-1-yl, but-2-en-2-yl, buta-1,3-dien-1-yl, buta-1,3-dien-2-yl, cyclobut-1-en-1-yl, cyclobut-1-en-3-yl, cyclobuta-1,3-dien-1-yl, but-1-yn-1-yl, but-1-yn-3-yl, but-3-yn-1-yl, etc.; and the like. Where specific levels of saturation are intended, the nomenclature alkanyl, alkenyl and/or alkynyl is used, as defined below. As used herein, lower alkyl means (C1-C8) alkyl.

[0068] Alkanyl by itself or as part of another substituent refers to a saturated branched, straight-chain or cyclic alkyl derived by the removal of one hydrogen atom from a single carbon atom of a parent alkane. Typical alkanyl groups include, but are not limited to, methanyl; ethanyl; propanyls such as propan-1-yl, propan-2-yl (isopropyl), cyclopropan-1-yl, etc.; butanyls such as butan-1-yl, butan-2-yl (sec-butyl), 2-methyl-propan-1-yl (isobutyl), 2-methyl-propan-2-yl (t-butyl), cyclobutan-1-yl, etc.; and the like. As used herein, lower alkanyl means (C1-C8) alkanyl.

[0069] Alkenyl by itself or as part of another substituent refers to an unsaturated branched, straight-chain or cyclic alkyl having at least one carbon-carbon double bond derived by the removal of one hydrogen atom from a single carbon atom of a parent alkene. The group may be in either the cis or trans conformation about the double bond(s). Typical alkenyl groups include, but are not limited to, ethenyl; propenyls such as prop-1-en-1-yl, prop-1-en-2-yl, prop-2-en-1-yl, prop-2-en-2-yl, cycloprop-1-en-1-yl; cycloprop-2-en-1-yl; butenyls such as but-1-en-1-yl, but-1-en-2-yl, 2-methyl-prop-1-en-1-yl, but-2-en-1-yl, but-2-en-2-yl, buta-1,3-dien-1-yl, buta-1,3-dien-2-yl, cyclobut-1-en-1-yl, cyclobut-1-en-3-yl, cyclobuta-1,3-dien-1-yl, etc.; and the like. As used herein, lower alkenyl means (C2-C8) alkenyl.

[0070] Alkynyl by itself or as part of another substituent refers to an unsaturated branched, straight-chain or cyclic alkyl having at least one carbon-carbon triple bond derived by the removal of one hydrogen atom from a single carbon atom of a parent alkyne. Typical alkynyl groups include, but are not limited to, ethynyl; propynyls such as prop-1-yn-1-yl, prop-2-yn-1-yl, etc.; butynyls such as but-1-yn-1-yl, but-1-yn-3-yl, but-3-yn-1-yl, etc.; and the like. As used herein, lower alkynyl means (C2-C8) alkynyl.

[0071] Alkyldiyl by itself or as part of another substituent refers to a saturated or unsaturated, branched, straight-chain or cyclic divalent hydrocarbon group having the stated number of carbon atoms (i.e., C1-C6 means from one to six carbon atoms) derived by the removal of one hydrogen atom from each of two different carbon atoms of a parent alkane, alkene or alkyne, or by the removal of two hydrogen atoms from a single carbon atom of a parent alkane, alkene or alkyne. The two monovalent radical centers or each valency of the divalent radical center can form bonds with the same or different atoms. Typical alkyldiyl groups include, but are not limited to, methandiyl; ethyldiyls such as ethan-1,1-diyl, ethan-1,2-diyl, ethen-1,1-diyl, ethen-1,2-diyl; propyldiyls such as propan-1,1-diyl, propan-1,2-diyl, propan-2,2-diyl, propan-1,3-diyl, cyclopropan-1,1-diyl, cyclopropan-1,2-diyl, prop-1-en-1,1-diyl, prop-1-en-1,2-diyl, prop-2-en-1,2-diyl, prop-1-en-1,3-diyl, cycloprop-1-en-1,2-diyl, cycloprop-2-en-1,2-diyl, cycloprop-2-en-1,1-diyl, prop-1-yn-1,3-diyl, etc.; butyldiyls such as, butan-1,1-diyl, butan-1,2-diyl, butan-1,3-diyl, butan-1,4-diyl, butan-2,2-diyl, 2-methyl-propan-1,1-diyl, 2-methyl-propan-1,2-diyl, cyclobutan-1,1-diyl; cyclobutan-1,2-diyl, cyclobutan-1,3-diyl, but-1-en-1,1-diyl, but-1-en-1,2-diyl, but-1-en-1,3-diyl, but-1-en-1,4-diyl, 2-methyl-prop-1-en-1,1-diyl, 2-methanylidene-propan-1,1-diyl, buta-1,3-dien-1,1-diyl, buta-1,3-dien-1,2-diyl, buta-1,3-dien-1,3-diyl, buta-1,3-dien-1,4-diyl, cyclobut-1-en-1,2-diyl, cyclobut-1-en-1,3-diyl, cyclobut-2-en-1,2-diyl, cyclobuta-1,3-dien-1,2-diyl, cyclobuta-1,3-dien-1,3-diyl, but-1-yn-1,3-diyl, but-1-yn-1,4-diyl, buta-1,3-diyn-1,4-diyl, etc.; and the like. Where specific levels of saturation are intended, the nomenclature alkanyldiyl, alkenyldiyl and/or alkynyldiyl is used. Where it is specifically intended that the two valencies are on the same carbon atom, the nomenclature alkylidene is used. In some embodiments, the alkyldiyl group is (C1-C8) alkyldiyl. Specific embodiments include saturated acyclic alkanyldiyl groups in which the radical centers are at the terminal carbons, e.g., methandiyl (methano); ethan-1,2-diyl (ethano); propan-1,3-diyl (propano); butan-1,4-diyl (butano); and the like (also referred to as alkylenos, defined infra).

[0072] Alkyleno by itself or as part of another substituent refers to a straight-chain saturated or unsaturated alkyldiyl group having two terminal monovalent radical centers derived by the removal of one hydrogen atom from each of the two terminal carbon atoms of straight-chain parent alkane, alkene or alkyne. The locant of a double bond or triple bond, if present, in a particular alkyleno is indicated in square brackets. Typical alkyleno groups include, but are not limited to, methano; ethylenos such as ethano, etheno, ethyno; propylenos such as propano, prop[1]eno, propa[1,2]dieno, prop[1]yno, etc.; butylenos such as butano, but[1]eno, but[2]eno, buta[1,3]dieno, but[1]yno, but[2]yno, buta[1,3]diyno, etc.; and the like. Where specific levels of saturation are intended, the nomenclature alkano, alkeno and/or alkyno is used. In some embodiments, the alkyleno group is (C1-C8) or (C1-C3) alkyleno. Specific embodiments include straight-chain saturated alkano groups, e.g., methano, ethano, propano, butano, and the like.

[0073] Heteroalkyl, Heteroalkanyl, Heteroalkenyl, Heteroalkynyl, Heteroalkyldiyl and Heteroalkyleno by themselves or as part of another substituent refer to alkyl, alkanyl, alkenyl, alkynyl, alkyldiyl and alkyleno groups, respectively, in which one or more of the carbon atoms are each independently replaced with the same or different heteratoms or heteroatomic groups. Typical heteroatoms and/or heteroatomic groups which can replace the carbon atoms include, but are not limited to, O, S, SO, NR, PH, S(O), S(O).sub.2, S(O) NR, S(O).sub.2NR, and the like, including combinations thereof, where each R.sup.f is independently hydrogen or (C1-C8) alkyl.

[0074] Cycloalkyl and Heterocycloalkyl by themselves or as part of another substituent refer to cyclic versions of alkyl and heteroalkyl groups, respectively. For heteroalkyl groups, a heteroatom can occupy the position that is attached to the remainder of the molecule. Typical cycloalkyl groups include, but are not limited to, cyclopropyl; cyclobutyls such as cyclobutanyl and cyclobutenyl; cyclopentyls such as cyclopentanyl and cyclopentenyl; cyclohexyls such as cyclohexanyl and cyclohexenyl; and the like. Typical heterocycloalkyl groups include, but are not limited to, tetrahydrofuranyl (e.g., tetrahydrofuran-2-yl, tetrahydrofuran-3-yl, etc.), piperidinyl (e.g., piperidin-1-yl, piperidin-2-yl, etc.), morpholinyl (e.g., morpholin-3-yl, morpholin-4-yl, etc.), piperazinyl (e.g., piperazin-1-yl, piperazin-2-yl, etc.), and the like.

[0075] Acyclic Heteroatomic Bridge refers to a divalent bridge in which the backbone atoms are exclusively heteroatoms and/or heteroatomic groups. Typical acyclic heteroatomic bridges include, but are not limited to, O, S, SO, NR, PH, S(O), S(O).sub.2, S(O) NR, S(O).sub.2NR, and the like, including combinations thereof, where each R is independently hydrogen or (C1-C8) alkyl.

[0076] Parent Aromatic Ring System refers to an unsaturated cyclic or polycyclic ring system having a conjugated electron system. Specifically included within the definition of parent aromatic ring system are fused ring systems in which one or more of the rings are aromatic and one or more of the rings are saturated or unsaturated, such as, for example, fluorene, indane, indene, phenalene, tetrahydronaphthalene, etc. Typical parent aromatic ring systems include, but are not limited to, aceanthrylene, acenaphthylene, acephenanthrylene, anthracene, azulene, benzene, chrysene, coronene, fluoranthene, fluorene, hexacene, hexaphene, hexalene, indacene, s-indacene, indane, indene, naphthalene, octacene, octaphene, octalene, ovalene, penta-2,4-diene, pentacene, pentalene, pentaphene, perylene, phenalene, phenanthrene, picene, pleiadene, pyrene, pyranthrene, rubicene, tetrahydronaphthalene, triphenylene, trinaphthalene, and the like.

[0077] Aryl by itself or as part of another substituent refers to a monovalent aromatic hydrocarbon group having the stated number of carbon atoms (i.e., C6-C15 means from 6 to 15 carbon atoms) derived by the removal of one hydrogen atom from a single carbon atom of a parent aromatic ring system. Typical aryl groups include, but are not limited to, groups derived from aceanthrylene, acenaphthylene, acephenanthrylene, anthracene, azulene, benzene, chrysene, coronene, fluoranthene, fluorene, hexacene, hexaphene, hexalene, as-indacene, s-indacene, indane, indene, naphthalene, octacene, octaphene, octalene, ovalene, pentacene, pentalene, pentaphene, perylene, phenalene, phenanthrene, picene, pleiadene, pyrene, pyranthrene, rubicene, triphenylene, trinaphthalene, and the like, as well as the various hydro isomers thereof. In preferred embodiments, the aryl group is (C6-C15) aryl, with (C6-C10) being more typical. Specific exemplary aryls include phenyl and naphthyl.

[0078] Arylaryl by itself or as part of another substituent refers to a monovalent hydrocarbon group derived by the removal of one hydrogen atom from a single carbon atom of a ring system in which two or more identical or non-identical parent aromatic ring systems are joined directly together by a single bond, where the number of such direct ring junctions is one less than the number of parent aromatic ring systems involved. Typical arylaryl groups include, but are not limited to, biphenyl, triphenyl, phenyl-naphthyl, binaphthyl, biphenyl-naphthyl, and the like. Where the number of carbon atoms in an arylaryl group are specified, the numbers refer to the carbon atoms comprising each parent aromatic ring. For example, (C6-C15) arylaryl is an arylaryl group in which each aromatic ring comprises from 6 to 15 carbons, e.g., biphenyl, triphenyl, binaphthyl, phenylnaphthyl, etc. In some embodiments, each parent aromatic ring system of an arylaryl group is independently a (C6-C15) aromatic, more preferably a (C6-C10) aromatic. Specific exemplary arylaryl groups include those in which all of the parent aromatic ring systems are identical, e.g., biphenyl, triphenyl, binaphthyl, trinaphthyl, etc.

[0079] Biaryl by itself or as part of another substituent refers to an arylaryl group having two identical parent aromatic systems joined directly together by a single bond. Typical biaryl groups include, but are not limited to, biphenyl, binaphthyl, bianthracyl, and the like. In some embodiments, the aromatic ring systems are (C6-C15) aromatic rings, more typically (C6-C10) aromatic rings. A particular exemplary biaryl group is biphenyl.

[0080] Arylalkyl by itself or as part of another substituent refers to an acyclic alkyl group in which one of the hydrogen atoms bonded to a carbon atom, typically a terminal or sp.sup.3 carbon atom, is replaced with an aryl group. Typical arylalkyl groups include, but are not limited to, benzyl, 2-phenylethan-1-yl, 2-phenylethen-1-yl, naphthylmethyl, 2-naphthylethan-1-yl, 2-naphthylethen-1-yl, naphthobenzyl, 2-naphthophenylethan-1-yl and the like. Where specific alkyl moieties are intended, the nomenclature arylalkanyl, arylakenyl and/or arylalkynyl is used. In some embodiments, the arylalkyl group is (C7-C21) arylalkyl, e.g., the alkanyl, alkenyl or alkynyl moiety of the arylalkyl group is (C1-C6) and the aryl moiety is (C6-C15). In some specific embodiments the arylalkyl group is (C7-C13), e.g., the alkanyl, alkenyl or alkynyl moiety of the arylalkyl group is (C1-C3) and the aryl moiety is (C6-C10).

[0081] Parent Heteroaromatic Ring System refers to a parent aromatic ring system in which one or more carbon atoms are each independently replaced with the same or different heteroatoms or heteroatomic groups. Typical heteroatoms or heteroatomic groups to replace the carbon atoms include, but are not limited to, N, NH, P, O, S, S(O), S(O).sub.2, Si, etc. Specifically included within the definition of parent heteroaromatic ring systems are fused ring systems in which one or more of the rings are aromatic and one or more of the rings are saturated or unsaturated, such as, for example, benzodioxan, benzofuran, chromane, chromene, indole, indoline, xanthene, etc. Also included in the definition of parent heteroaromatic ring system are those recognized rings that include common substituents, such as, for example, benzopyrone and 1-methyl-1,2,3,4-tetrazole. Specifically excluded from the definition of parent heteroaromatic ring system are benzene rings fused to cyclic polyalkylene glycols such as cyclic polyethylene glycols. Typical parent heteroaromatic ring systems include, but are not limited to, acridine, benzimidazole, benzisoxazole, benzodioxan, benzodioxole, benzofuran, benzopyrone, benzothiadiazole, benzothiazole, benzotriazole, benzoxaxine, benzoxazole, benzoxazoline, carbazole, O-carboline, chromane, chromene, cinnoline, furan, imidazole, indazole, indole, indoline, indolizine, isobenzofuran, isochromene, isoindole, isoindoline, isoquinoline, isothiazole, isoxazole, naphthyridine, oxadiazole, oxazole, perimidine, phenanthridine, phenanthroline, phenazine, phthalazine, pteridine, purine, pyran, pyrazine, pyrazole, pyridazine, pyridine, pyrimidine, pyrrole, pyrrolizine, quinazoline, quinoline, quinolizine, quinoxaline, tetrazole, thiadiazole, thiazole, thiophene, triazole, xanthene, and the like.

[0082] Heteroaryl by itself or as part of another substituent refers to a monovalent heteroaromatic group having the stated number of ring atoms (e.g., 5-14 membered means from 5 to 14 ring atoms) derived by the removal of one hydrogen atom from a single atom of a parent heteroaromatic ring system. Typical heteroaryl groups include, but are not limited to, groups derived from acridine, benzimidazole, benzisoxazole, benzodioxan, benzodiaxole, benzofuran, benzopyrone, benzothiadiazole, benzothiazole, benzotriazole, benzoxazine, benzoxazole, benzoxazoline, carbazole, O-carboline, chromane, chromene, cinnoline, furan, imidazole, indazole, indole, indoline, indolizine, isobenzofuran, isochromene, isoindole, isoindoline, isoquinoline, isothiazole, isoxazole, naphthyridine, oxadiazole, oxazole, perimidine, phenanthridine, phenanthroline, phenazine, phthalazine, pteridine, purine, pyran, pyrazine, pyrazole, pyridazine, pyridine, pyrimidine, pyrrole, pyrrolizine, quinazoline, quinoline, quinolizine, quinoxaline, tetrazole, thiadiazole, thiazole, thiophene, triazole, xanthene, and the like, as well as the various hydro isomers thereof. In preferred embodiments, the heteroaryl group is a 5-14 membered heteroaryl, with 5-10 membered heteroaryl being particularly preferred.

[0083] Heteroaryl-Heteroaryl by itself or as part of another substituent refers to a monovalent heteroaromatic group derived by the removal of one hydrogen atom from a single atom of a ring system in which two or more identical or non-identical parent heteroaromatic ring systems are joined directly together by a single bond, where the number of such direct ring junctions is one less than the number of parent heteroaromatic ring systems involved. Typical heteroaryl-heteroaryl groups include, but are not limited to, bipyridyl, tripyridyl, pyridylpurinyl, bipurinyl, etc. Where the number of atoms are specified, the numbers refer to the number of atoms comprising each parent heteroaromatic ring systems. For example, 5-15 membered heteroaryl-heteroaryl is a heteroaryl-heteroaryl group in which each parent heteroaromatic ring system comprises from 5 to 15 atoms, e.g., bipyridyl, tripuridyl, etc. In some embodiments, each parent heteroaromatic ring system is independently a 5-15 membered heteroaromatic, more typically a 5-10 membered heteroaromatic. Specific exemplary heteroaryl-heteroaryl groups include those in which all of the parent heteroaromatic ring systems are identical.

[0084] Biheteroaryl by itself or as part of another substituent refers to a heteroaryl-heteroaryl group having two identical parent heteroaromatic ring systems joined directly together by a single bond. Typical biheteroaryl groups include, but are not limited to, bipyridyl, bipurinyl, biquinolinyl, and the like. In some embodiments, the heteroaromatic ring systems are 5-15 membered heteroaromatic rings, more typically 5-10 membered heteroaromatic rings.

[0085] Heteroarylalkyl by itself or as part of another substituent refers to an acyclic alkyl group in which one of the hydrogen atoms bonded to a carbon atom, typically a terminal or sp.sup.3 carbon atom, is replaced with a heteroaryl group. Where specific alkyl moieties are intended, the nomenclature heteroarylalkanyl, heteroarylakenyl and/or heteroarylalkynyl is used. In some embodiments, the heteroarylalkyl group is a 6-21 membered heteroarylalkyl, e.g., the alkanyl, alkenyl or alkynyl moiety of the heteroarylalkyl is (C1-C6) alkyl and the heteroaryl moiety is a 5-15-membered heteroaryl. In some specific exemplary embodiments, the heteroarylalkyl is a 6-13 membered heteroarylalkyl, e.g., the alkanyl, alkenyl or alkynyl moiety is (C1-C3) alkyl and the heteroaryl moiety is a 5-10 membered heteroaryl.

[0086] Halogen or Halo by themselves or as part of another substituent, unless otherwise stated, refer to fluoro, chloro, bromo and iodo.

[0087] Haloalkyl by itself or as part of another substituent refers to an alkyl group in which one or more of the hydrogen atoms is replaced with a halogen. Thus, the term haloalkyl is meant to include monohaloalkyls, dihaloalkyls, trihaloalkyls, etc. up to perhaloalkyls. For example, the expression (C1-C2) haloalkyl includes fluoromethyl, difluoromethyl, trifluoromethyl, 1-fluoroethyl, 1,1-difluoroethyl, 1,2-difluoroethyl, 1,1,1-trifluoroethyl, perfluoroethyl, etc.

[0088] The above-defined groups may include prefixes and/or suffixes that are commonly used in the art to create additional well-recognized substituent groups. As examples, alkyloxy or alkoxy refers to a group of the formula OR, alkylamine refers to a group of the formula NHR and dialkylamine refers to a group of the formula NRR, where each R is independently an alkyl. As another example, haloalkoxy or haloalkyloxy refers to a group of the formula OR, where R is a haloalkyl.

[0089] Substituted, when used to modify a specified group or radical, means that one or more hydrogen atoms of the specified group or radical are each, independently of one another, replaced with the same or different substituent(s). Substituent groups useful for substituting for hydrogens on saturated carbon atoms in the specified group or radical include, but are not limited to R.sup.60, halo, O.sup.M.sup.+, O, OR.sup.70, SR.sup.70, S.sup.M.sup.+, S, NR.sup.80R.sup.80, NR.sup.70, NOR.sup.70, trihalomethyl, CF.sub.3, CN, OCN, SCN, NO, NO.sub.2, N.sub.2, N.sub.3, S(O).sub.2R.sup.70, S(O).sub.2O.sup.M.sup.+, S(O).sub.2OR.sup.70, OS(O).sub.2R.sup.70, OS(O).sub.2O.sup.M.sup.+, OS(O).sub.2OR.sup.70, P(O)(O.sup.).sub.2(M.sup.+).sub.2, P(O)(OR.sup.70)O.sup.M.sup.+, P(O)(OR.sup.70)(OR.sup.70), C(O)R.sup.70, C(S)R.sup.70, C(NR.sup.70)R.sup.70, C(O)O.sup.M.sup.+, C(O)OR.sup.70, C(S)OR.sup.70, C(O)NR.sup.80R.sup.80, C(NR.sup.70)NR.sup.80R.sup.80, OC(O)R.sup.70, OC(S)R.sup.70, OC(O)O.sup.M.sup.+, OC(O)OR.sup.70, OC(S)OR.sup.70, NR.sup.70C(O)R.sup.70, NR.sup.70C(S)R.sup.70, NR.sup.70C(O)O.sup.M.sup.+, NR.sup.70C(O)OR.sup.70, NR.sup.70C(S)OR.sup.70, NR.sup.70C(O)NR.sup.80R.sup.80, NR.sup.70C(NR.sup.70)R.sup.70 and NR.sup.70C(NR.sup.70)NR.sup.80R.sup.80, where R.sup.60 is selected from the group consisting of alkyl, cycloalkyl, heteroalkyl, cycloheteroalkyl, aryl, arylalkyl, heteroaryl and heteroarylalkyl; each R.sup.70 is independently hydrogen or R.sup.60; each R.sup.80 is independently R.sup.70 or alternatively, the two R.sup.80's, taken together with the nitrogen atom to which they are bonded, form a 5-, 6- or 7-membered cycloheteroalkyl which may optionally include from 1 to 4 of the same or different additional heteroatoms selected from the group consisting of O, N and S; and each M.sup.+ is a counter ion with a positive charge, for example, a positive charge independently selected from K.sup.+, Na.sup.+, .sup.+N(R.sup.60).sub.4, and Li.sup.+, or two of M.sup.+, combine to form a divalent counterion, for example a divalent counterion selected from Ca.sup.2+, Mg.sup.2+, and Ba.sup.2+. As specific examples, NR.sup.80R.sup.80 is meant to include NH.sub.2, NH-alkyl, N-pyrrolidinyl and N-morpholinyl.

[0090] Similarly, substituent groups useful for substituting for hydrogens on unsaturated carbon atoms in the specified group or radical include, but are not limited to, R.sup.60, halo, O.sup.M.sup.+, OR.sup.70, SR.sup.70, S.sup.M.sup.+, NR.sup.80R.sup.80, trihalomethyl, CF.sub.3, CN, OCN, SCN, NO, NO.sub.2, N.sub.3, S(O).sub.2R.sup.70, S(O).sub.2O.sup.M.sup.+, S(O).sub.2OR.sup.70, OS(O).sub.2R.sup.70, OS(O).sub.2O.sup.M.sup.+, OS(O).sub.2OR.sup.70, P(O)(O.sup.).sub.2(M.sup.+).sub.2, P(O)(OR.sup.70)O.sup.M.sup.+, P(O)(OR.sup.70)(OR.sup.70), C(O)R.sup.70, C(S)R.sup.70, C(NR.sup.70)R.sup.70, C(O)O.sup.M.sup.+, C(O)OR.sup.70, C(S)OR.sup.70, C(O)NR.sup.80R.sup.80, C(NR.sup.70)NR.sup.80R.sup.80, OC(O)R.sup.70, OC(S)R.sup.70, OC(O)O.sup.M.sup.+, OC(O)OR.sup.70, OC(S)OR.sup.70, NR.sup.70C(O)R.sup.70, NR.sup.70C(S)R.sup.70, NR.sup.70C(O)O.sup.M.sup.+, NR.sup.70C(O)OR.sup.70, NR.sup.70C(S)OR.sup.70, NR.sup.70C(O)NR.sup.80R.sup.80, NR.sup.70C(NR.sup.70)R.sup.70 and NR.sup.70C(NR.sup.70)NR.sup.80R.sup.80, where R.sup.60, R.sup.70, R.sup.80 and M.sup.+ are as previously defined.

[0091] Substituent groups, other than R.sup.p, useful for substituting for hydrogens on nitrogen atoms in heteroalkyl and cycloheteroalkyl groups include, but are not limited to, R.sup.60, O.sup.M.sup.+, OR.sup.70, SR.sup.70, S.sup.M.sup.+, NR.sup.80R.sup.80, trihalomethyl, CF.sub.3, CN, NO, NO.sub.2, S(O).sub.2R.sup.70, S(O).sub.2O.sup.M.sup.+, S(O).sub.2OR.sup.70, OS(O).sub.2R.sup.70, OS(O).sub.2O.sup.M.sup.+, OS(O).sub.2OR.sup.70, P(O)(O.sup.).sub.2(M.sup.+).sub.2, P(O)(OR.sup.70)O.sup.M.sup.+, P(O)(OR.sup.70)(OR.sup.70), C(O)R.sup.70, C(S)R.sup.70, C(NR.sup.70)R.sup.70, C(O)OR.sup.70, C(S)OR.sup.70, C(O)NR.sup.80R.sup.80, C(NR.sup.70)NR.sup.80R.sup.80, OC(O)R.sup.70, OC(S)R.sup.70, OC(O)OR.sup.70, OC(S)OR.sup.70, NR.sup.70C(O)R.sup.70, NR.sup.70C(S)R.sup.70, NR.sup.70C(O)OR.sup.70, NR.sup.70C(S)OR.sup.70, NR.sup.70C(O)NR.sup.80R.sup.80, NR.sup.70C(NR.sup.70)R.sup.70 and NR.sup.70C(NR.sup.70)NR.sup.80R.sup.80, where R.sup.60, R.sup.70, R.sup.80 and M.sup.+ are as previously defined.

[0092] Substituent groups from the above lists useful for substituting other groups or atoms specified as substituted will be apparent to those of skill in the art.

[0093] Protecting group refers to a group of atoms that, when attached to a reactive functional group in a molecule, mask, reduce or prevent the reactivity of the functional group. Typically, a protecting group may be selectively removed as desired during the course of a synthesis. Examples of protecting groups can be found in Greene and Wuts, Protective Groups in Organic Chemistry, 3.sup.rd Ed., 1999, John Wiley & Sons, NY and Harrison et al., Compendium of Synthetic Organic Methods, Vols. 1-8, 1971-1996, John Wiley & Sons, NY. Representative amino protecting groups include, but are not limited to, formyl, acetyl, trifluoroacetyl, benzyl, benzyloxycarbonyl (CBZ), tert-butoxycarbonyl (Boc), trimethylsilyl (TMS), 2-trimethylsilyl-ethanesulfonyl (TES), trityl and substituted trityl groups, allyloxycarbonyl, 9-fluorenylmethyloxycarbonyl (FMOC), nitro-veratryloxycarbonyl (NVOC) and the like. Representative hydroxyl protecting groups include, but are not limited to, those where the hydroxyl group is either acylated or alkylated such as benzyl and trityl ethers, as well as alkyl ethers, tetrahydropyranyl ethers, trialkylsilyl ethers (e.g., TMS or TIPPS groups) and allyl ethers.

[0094] Fc Receptor refers to a member of the family of cell surface molecules that binds the Fc portion (containing the specific constant region) of an immunoglobulin. Each Fc receptor binds immunoglobulins of a specific type. For example the Fc receptor (FcR) binds IgA, the FcR binds IgE and the FcR binds IgG.

[0095] The FcR family includes the polymeric Ig receptor involved in epithelial transport of IgA/IgM, the mycloid specific receptor RcRI (also called CD89), the Fc/R and at least two alternative IgA receptors (for a recent review see Monteiro & van de Winkel, 2003, Annu. Rev. Immunol, advanced e-publication). The FcRI is expressed on neutrophils, eosinophils, monocytes/macrophages, dendritic cells and kupfer cells. The FcRI includes one alpha chain and the FcR gamma homodimer that bears an activation motif (ITAM) in the cytoplasmic domain and phosphorylates Syk kinase.

[0096] The FcR family includes two types, designated FcRI and FcRII (also known as CD23). FcRI is a high affinity receptor (binds IgE with an affinity of about 10.sup.10M.sup.1) found on mast, basophil and eosinophil cells that anchors monomeric IgE to the cell surface. The FcRI possesses one alpha chain, one beta chain and the gamma chain homodimer discussed above. The FcRII is a low affinity receptor expressed on mononuclear phagocytes, B lymphocytes, eosinophils and platelets. The FcRII comprises a single polypeptide chain and does not include the gamma chain homodimer.

[0097] The FcR family includes three types, designated FcRI (also known as CD64), FcRII (also known as CD32) and FcRIII (also known as CD16). FcRI is a high affinity receptor (binds IgG1 with an affinity of 10.sup.8M.sup.1) found on mast, basophil, mononuclear, neutrophil, eosinophil, dendritic and phagocyte cells that anchors nomomeric IgG to the cell surface. The FcRI includes one alpha chain and the gamma chain dimer shared by FcRI and FcRI.

[0098] The FcRII is a low affinity receptor expressed on neutrophils, monocytes, eosinophils, platelets and B lymphocytes. The FcRII includes one alpha chain, and does not include the gamma chain homodimer discussed above.

[0099] The FcRIII is a low affinity (binds IgG1 with an affinity of 510.sup.5M.sup.1) expressed on NK, eosinophil, macrophage, neutrophil and mast cells. It comprises one alpha chain and the gamma homodimer shared by FcRI, FcRI and FcRI.

[0100] Skilled artisans will recognize that the subunit structure and binding properties of these various Fc receptors, as well as the cell types expressing them, are not completely characterized. The above discussion merely reflects the current state-of-the-art regarding these receptors (see, e.g., Immunobiology: The Immune System in Health & Disease, 5.sup.th Edition, Janeway et al., Eds, 2001, ISBN 0-8153-3642-x, FIG. 9.30 at pp. 371), and is not intended to be limiting with respect to the myriad receptor signaling cascades that can be regulated with the prodrugs described herein.

[0101] Fc Receptor-Mediated Degranulation or Fc Receptor-Induced Degranulation refers to degranulation that proceeds via an Fc receptor signal transduction cascade initiated by crosslinking of an Fc receptor.

[0102] IgE-Induced Degranulation or FcRI-Mediated Degranulation refers to degranulation that proceeds via the IgE receptor signal transduction cascade initiated by crosslinking of FcR1-bound IgE. The crosslinking may be induced by an IgE-specific allergen or other multivalent binding agent, such as an anti-IgE antibody. In mast and/or basophil cells, the FcRI signaling cascade leading to degranulation may be broken into two stages: upstream and downstream. The upstream stage includes all of the processes that occur prior to calcium ion mobilization. The downstream stage includes calcium ion mobilization and all processes downstream thereof. Compounds that inhibit FcRI-mediated degranulation may act at any point along the FcRI-mediated signal transduction cascade. Compounds that selectively inhibit upstream FcRI-mediated degranulation act to inhibit that portion of the FcRI signaling cascade upstream of the point at which calcium ion mobilization is induced. In cell-based assays, compounds that selectively inhibit upstream FcRI-mediated degranulation inhibit degranulation of cells such as mast or basophil cells that are activated or stimulated with an IgE-specific allergen or binding agent (such as an anti-IgE antibody) but do not appreciably inhibit degranulation of cells that are activated or stimulated with degranulating agents that bypass the FcRI signaling pathway, such as, for example the calcium ionophores ionomycin and A23187.

[0103] IgG-Induced Degranulation or FcRI-Mediated Degranulation refers to degranulation that proceeds via the FcRI signal transduction cascade initiated by crosslinking of FcRI-bound IgG. The crosslinking may be induced by an IgG-specific allergen or another multivalent binding agent, such as an anti-IgG or fragment antibody. Like the FcRI signaling cascade, in mast and basophil cells the FcRI signaling cascade also leads to degranulation which may be broken into the same two stages: upstream and downstream. Similar to FcRI-mediated degranulation, compounds that selectively inhibit upstream FcRI-mediated degranulation act upstream of the point at which calcium ion mobilization is induced. In cell-based assays, compounds that selectively inhibit upstream FcRI-mediated degranulation inhibit degranulation of cells such as mast or basophil cells that are activated or stimulated with an IgG-specific allergen or binding agent (such as an anti-IgG antibody or fragment) but do not appreciably inhibit degranulation of cells that are activated or stimulated with degranulating agents that bypass the FcRI signaling pathway, such as, for example the calcium ionophores ionomycin and A23187.

[0104] Ionophore-Induced Degranulation or Ionophore-Mediated Degranulation refers to degranulation of a cell, such as a mast or basophil cell, that occurs upon exposure to a calcium ionophore such as, for example, ionomycin or A23187.

[0105] Syk Kinase refers to the well-known 72 kDa non-receptor (cytoplasmic) spleen protein tyrosine kinase expressed in B-cells and other hematopoetic cells. Syk kinase includes two consensus Src-homology 2 (SH2) domains in tandem that bind to phosphorylated immunoreceptor tyrosine-based activation motifs (ITAMs), a linker domain and a catalytic domain (for a review of the structure and function of Syk kinase see Sada et al., 2001, J. Biochem. (Tokyo) 130:177-186); see also Turner et al., 2000, Immunology Today 21:148-154). Syk kinase has been extensively studied as an effector of B-cell receptor (BCR) signaling (Turner et al., 2000, supra). Syk kinase is also critical for tyrosine phosphorylation of multiple proteins which regulate important pathways leading from immunoreceptors, such as Ca.sup.2+ mobilization and mitogen-activated protein kinase (MAPK) cascades and degranulation. Syk kinase also plays a critical role in integrin signaling in neutrophils (see, e.g., Mocsai et al. 2002, Immunity 16:547-558).

[0106] As used herein, Syk kinase includes kinases from any species of animal, including but not limited to, homosapiens, simian, bovine, porcine, rodent, etc., recognized as belonging to the Syk family. Specifically included are isoforms, splice variants, allelic variants, mutants, both naturally occurring and man-made. The amino acid sequences of such Syk kinases are well known and available from GENBANK. Specific examples of mRNAs encoding different isoforms of human Syk kinase can be found at GENBANK accession no. gi|21361552|ref|NM_003177.2|, gi|496899|emb|Z29630.1|HSSYKPTK[496899] and gi|15030258|gb|BC011399.1|BC011399[15030258], which are incorporated herein by reference.

[0107] Skilled artisans will appreciate that tyrosine kinases belonging to other families may have active sites or binding pockets that are similar in three-dimensional structure to that of Syk. As a consequence of this structural similarity, such kinases, referred to herein as Syk mimics, are expected to catalyze phosphorylation of substrates phosphorylated by Syk. Thus, it will be appreciated that such Syk mimics, signal transduction cascades in which such Syk mimics play a role, and biological responses effected by such Syk mimics and Syk mimic-dependent signaling cascades may be regulated, and in particular inhibited, with many of the prodrugs described herein.

[0108] Syk-Dependent Signaling Cascade refers to a signal transduction cascade in which Syk kinase plays a role. Non-limiting examples of such Syk-dependent signaling cascades include the FcRI, FcRI, FcRI, FcRIII, BCR and integrin signaling cascades.

[0109] Autoimmune Disease refers to those diseases which are commonly associated with the nonanaphylactic hypersensitivity reactions (Type II, Type III and/or Type IV hypersensitivity reactions) that generally result as a consequence of the subject's own humoral and/or cell-mediated immune response to one or more immunogenic substances of endogenous and/or exogenous origin. Such autoimmune diseases are distinguished from diseases associated with the anaphylactic (Type I or IgE-mediated) hypersensitivity reactions.

6.2 the Prodrug Compounds

[0110] As described in the Summary, the instant disclosure provides prodrugs of biologically active 2,4-pyrimidinediamine compounds, such as the various 2,4-pyrimidinediamine compounds described in U.S. application Ser. No. 10/355,543 filed Jan. 31, 2003 (US2004/0029902A1), international application Serial No. PCT/US03/03022 filed Jan. 31, 2003 (WO 03/063794), U.S. application Ser. No. 10/631,029 filed Jul. 29, 2003 (______), international application Serial No. PCT/US03/24087 (WO2004/014382), U.S. application Ser. No. 10/903,263 filed Jul. 30, 2004 (US2005/0234049), and international application Serial No. PCT/US2004/24716 (______), the disclosures of which are incorporated herein by reference. Prodrugs of these 2,4-pyrimidinediamine compounds are of particular interest, as these compounds inhibit upstream Fc receptor signaling cascades as well as Syk kinase and Syk kinase-dependent signaling cascades. The prodrugs generally include such active 2,4-pyrimidinediamine compounds in which one or more of the available primary or secondary amine groups is masked with a progroup R.sup.p that metabolizes in vivo by to yield the active 2,4 pyrimidinediamine drug. As also discussed in the Summary section, and as will be discussed in more detail, below, the nature of the progroup can vary, and will depend upon, among other factors, the desired water solubility of the prodrug, its intended mode of administration and/or its intended mechanism or site of metabolism to the active 2,4-pyrimidinediamine compound.

[0111] For example, it has been discovered that a specific active 2,4-pyrimidinediamine drug (Compound 1, below), exhibits vastly superior water solubility when formulated as a phosphate prodrug (Compound 4, below):

TABLE-US-00001 Compound Structure Solubility Compound 1 [00009] 1-2 g/ml Compound 4 [00010] >5 mg/ml

[0112] This prodrug Compound 4 also exhibits superior bioavailability compared to the corresponding active drug Compound 1 when administered orally to test animals. In fact, unlike the drug Compound 1, absorption of the prodrug Compound 4 is not dependent upon formulation. In pharmacokinetics studies carried out in rats, the prodrug Compound 4 was absorbed equally well from solutions (e.g., PEG-400 solutions and carboxymethylcellulose solutions) and powders (packed in hard gelatin capsules). While not intending to be bound by any particular theory of operation, it is believed that the improved oral bioavailability of the prodrug Compound 4, as well as its formulation-independent absorption, is due, at least in part, to its higher water-solubility. It is expected that other active 2,4-pyrimidinediamine compounds that have similarly low water solubilities, and hence oral bioavailabilities, will exhibit similar increases in water solubility and oral bioavailability when formulated as phosphate prodrugs.

[0113] Conversely, the corresponding phosphate ester prodrug of active drug Compound 1 would be expected to have lower water-solubility than the active Compound 1 compound. Thus, it is expected that phosphate ester prodrugs of active 2,4-pyrimidinediamine compounds that have lower water-solubility than the corresponding active 2,4-pyrimidinediamine compounds will be especially useful in applications and formulations where low water-solubility is desirable, such as formulations adapted for delivery via inhalation.

[0114] One class of active 2,4-pyrimidinediamine compounds that is expected to benefit from formulation as prodrugs, and in particular as phosphate prodrugs, includes 2,4-pyrimidinediamines in which the N4-substituent of the 2,4-pyrimidinediamine moiety is a substituted or unsubstituted nitrogen-containing heteroaryl ring of the formula

##STR00011##

where Z.sup.1 and Z.sup.2 are each, independently of one another, selected from CH and N and Y is selected from CH.sub.2, NH, O, S, S(O) and S(O).sub.2. Such prodrugs can include progroups R.sup.p at: one or both of the non-aromatic ring nitrogens of the heteroaryl ring, the N2-nitrogen of the 2,4-pyrimidinedimaine moiety, the N4-nitrogen atom of the 2,4-pyrimidinediamine moiety and/or any available nitrogen atoms in the substituent attached to the N2 nitrogen atom of the 2,4-pyrimidinediamine moiety.

[0115] In one illustrative embodiment, the prodrugs are compounds according to structural formula (I):

##STR00012##

[0116] including salts, solvates, hydrates and N-oxides thereof, wherein: [0117] Y is selected from CH.sub.2, NR.sup.24, O, S, S(O) and S(O).sub.2; [0118] Z.sup.1 and Z.sup.2 are each, independently of one another, selected from CH and N; [0119] R.sup.2 is selected from lower alkyl optionally substituted with one or more of the same or different R.sup.8 groups, lower cycloalkyl optionally substituted with one or more of the same or different R.sup.8 groups, cyclohexyl optionally substituted with one or more of the same or different R.sup.8 groups, 3-8 membered cycloheteroalkyl optionally substituted with one or more of the same or different R.sup.8 groups, (C6-C14) aryl optionally substituted with one or more of the same or different R.sup.8 groups, phenyl optionally substituted with one or more of the same or different R.sup.8 groups and 5-15 membered heteroaryl optionally substituted with one or more of the same or different R.sup.8 groups; [0120] R.sup.5 is selected from halo, fluoro, cyano, nitro, trihalomethyl and trifluoromethyl; [0121] R.sup.8 is selected from R.sup.a, R.sup.b, R.sup.a substituted with one or more, for example, from one to four, of the same or different R.sup.a or R.sup.b, OR.sup.a substituted with one or more of the same or different R.sup.a or R.sup.b, B(OR.sup.a).sub.2, B(NR.sup.cR.sup.c).sub.2, (CH.sub.2).sub.mR.sup.b, (CHR.sup.a).sub.mR.sup.b, O(CH.sub.2).sub.mR.sup.b, S(CH.sub.2).sub.mR.sup.b, OCHR.sup.aR.sup.b, OCR.sup.a(R.sup.b).sub.2, O(CHR.sup.a).sub.mR.sup.b, O (CH.sub.2).sub.mCH[(CH.sub.2).sub.mR.sup.b]R.sup.b, S(CHR.sup.a).sub.mR.sup.b, C(O)NH(CH.sub.2).sub.mR.sup.b, C(O)NH(CHR.sup.a).sub.mR.sup.b, O(CH.sub.2)C(O)NH(CH.sub.2).sub.mR.sup.b, S(CH.sub.2), C(O)NH(CH.sub.2), R.sup.b, O(CHR.sup.a), C(O)NH(CHR.sup.a), R.sup.b, S(CHR.sup.a).sub.mC(O)NH(CHR.sup.a).sub.mR.sup.b, NH(CH.sub.2).sub.mR.sup.b, NH(CHR.sup.a).sub.mR.sup.b, NH[(CH.sub.2).sub.mR.sup.b], N[(CH.sub.2).sub.mR.sup.b].sub.2, NHC(O)NH(CH.sub.2), R.sup.b, NHC(O)(CH.sub.2).sub.mCHR.sup.bR.sup.b and NH(CH.sub.2)C(O)NH(CH.sub.2)R.sup.b; [0122] R.sup.17 is selected from hydrogen, halogen, fluoro, lower alkyl and methyl or, alternatively, R.sup.17 may be taken together with R.sup.18 to form an oxo (O) group or, together with the carbon atom to which they are attached, a spirocycle containing from 3 to 7 carbon atoms; [0123] R.sup.18 is selected from hydrogen, halogen, fluoro, lower alkyl and methyl or, alternatively, R.sup.18 may be taken together with R.sup.17 to form an oxo (O) group or, together with the carbon atom to which they are attached, a spirocycle containing from 3 to 7 carbon atoms; [0124] R.sup.19 is selected from hydrogen, lower alkyl, and methyl or, alternatively, R.sup.19 may be taken together with R.sup.20 to form an oxo (O) group or, together with the carbon atom to which they are attached, a spirocycle containing from 3 to 7 carbon atoms; [0125] R.sup.20 is selected from hydrogen, lower alkyl and methyl or, alternatively, R.sup.20 may be taken together with R.sup.19 to form an oxo (O) group or, together with the carbon atom to which they are attached, a spirocycle containing from 3 to 7 carbon atoms; [0126] each R.sup.a is, independently of the others, selected from hydrogen, lower alkyl, lower cycloalkyl, cyclohexyl, (C4-C11) cycloalkylalkyl, (C6-C10) aryl, phenyl, (C7-C16) arylalkyl, benzyl, 2-6 membered heteroalkyl, 3-8 membered cycloheteroalkyl, morpholinyl, piperazinyl, homopiperazinyl, piperidinyl, 4-11 membered cycloheteroalkylalkyl, 5-10 membered heteroaryl and 6-16 membered heteroarylalkyl; [0127] each R.sup.b is a suitable group independently selected from O, OR.sup.a, (C1-C3) haloalkyloxy, S, SR.sup.a, NR.sup.a, NOR.sup.a, NR.sup.cR.sup.c, halogen, CF.sub.3, CN, NC, OCN, SCN, NO, NO.sub.2, N.sub.2, N.sub.3, S(O)R.sup.a, S(O).sub.2R.sup.a, S(O).sub.2OR.sup.a, S(O)NR.sup.cR.sup.c, S(O).sub.2NR.sup.cR.sup.c, OS(O)R.sup.a, OS(O).sub.2R.sup.a, OS(O).sub.2OR.sup.a, OS(O).sub.2NR.sup.cR.sup.c, C(O)R.sup.a, C(O)OR.sup.a, C(O)NR.sup.cR.sup.c, C(NH)NR.sup.cR.sup.c, C(NR.sup.a)NR.sup.cR.sup.c, C(NOH)R.sup.a, C(NOH)NR.sup.cR.sup.c, OC(O)R.sup.a, OC(O)OR.sup.a, OC(O)NR.sup.cR.sup.c, OC(NH)NR.sup.cR.sup.c, OC(NR.sup.a)NR.sup.cR.sup.c, [NHC(O)]R.sup.a, [NR.sup.aC(O)], R.sup.a, [NHC(O)].sub.nOR.sup.a, [NR.sup.aC(O)].sub.nOR.sup.a, [NHC(O)].sub.nNR.sup.cR.sup.c, [NR.sup.aC(O)].sub.nNR.sup.cR.sup.c, [NHC(NH)]NR.sup.cR.sup.c and [NR.sup.aC(NR.sup.a)].sub.nNR.sup.cR.sup.c; [0128] each R.sup.c is, independently of the others, selected from a protecting group and R.sup.a, or, alternatively, the two R.sup.c bonded to the same nitrogen atom are taken together with that nitrogen atom to form a 5 to 8-membered cycloheteroalkyl or heteroaryl which may optionally include one or more of the same or different additional heteroatoms and which may optionally be substituted with one or more, for example, from one to four, of the same or different R.sup.a groups; [0129] R.sup.21, R.sup.22 and R.sup.23 are each, independently of one another, selected from hydrogen and a progroup R.sup.p; [0130] R.sup.24 is selected from hydrogen, lower alkyl and progroup R.sup.P; [0131] each m is, independently of the others, an integer from 1 to 3; and [0132] each n is, independently of the others, an integer from 0 to 3, with the proviso that at least one of R.sup.21, R.sup.22, R.sup.23 and R.sup.24 is a progroup.

[0133] In the prodrugs described herein, and in particular in the prodrugs of structural formula (I), R.sup.21, R.sup.22 and R.sup.23 each represent either hydrogen or a progroup R.sup.p. Also, R.sup.24 represents hydrogen, a lower alkyl or a progroup R.sup.P. Thus, the prodrugs can include a single R.sup.P progroup, two R.sup.P progroups, three R.sup.P progroups, or even more R.sup.P progroups, depending, in part, on the identity of Y and whether the R.sup.2 substituent includes any R.sup.P progroups. In some embodiments, it is preferred that the prodrugs described herein, and in particular the prodrugs of structural formula (I), include only one R.sup.P group. Without intending to be bound by any theory of operation, it is possible that the different R.sup.P groups in prodrugs including more than one R.sup.P progroup may metabolize at different rates. Prodrugs including a single R.sup.P progroup would avoid such differential metabolic kinetics. A specific embodiment of prodrugs according to structural formula (I) that include a single progroup R.sup.P are compounds according to structural formula (Ia):

##STR00013##

[0134] wherein Y.sup.1 is selected from CH.sub.2, NR.sup.24, O, S, S(O) and S(O).sub.2; and Z.sup.2, R.sup.2, R.sup.5, R.sup.17, R.sup.18, R.sup.19, R.sup.20, R.sup.24 and R.sup.P are as previously defined, with the proviso that R.sup.2 does not include any R.sup.P groups.

[0135] The identity of any R.sup.P progroups present in the prodrugs described herein is not critical for success, provided that it hydrolyzes under the conditions of use to yield the active 2,4-pyrimidinediamine compound. It has recently been discovered that a phosphate-containing prodrug according to the structure illustrated below:

##STR00014##

metabolizes in vivo to the corresponding active 2,4-pyrimidinediamine compound (Compound 1), illustrated below:

##STR00015##

[0136] While not intending to be bound by any particular theory operation, it is believed that this prodrug metabolizes to active Compound 1 via the corresponding hydroxymethylamine intermediate illustrated below:

##STR00016##

[0137] Such hydroxymethylamine compound are known to be unstable under physiological conditions and various pH ranges where they hydrolyze in vivo to yield formaldehyde and the active drunot intending substance. Based on this observation, it is believed that prodrugs that include hydroxyl protecting groups that can be metabolized in vivo, for example by the acidic conditions of the stomach and/or by enzymes present in the digestive tract or other organs and/or tissues or fluids with the body, to yield the hydroxymethylamine intermediate illustrated above will likewise metabolize to the active 2,4 pyrimidinediamine drug.

[0138] Moreover, it is expected that the amino and thio analogs of this hydroxymethylamine intermediate, will be similarly unstable at physiological conditions and also hydrolyze in vivo to the active 2,4-pyrimdiendiamine drug. Accordingly, it is also expected that the corresponding amino and thio compounds, as well as compounds in which the -amino and -thio groups are masked with protecting groups that are removed under physiological conditions of use to yield the -amino and -thio groups, will likewise make suitable prodrugs.

[0139] Thus, in some embodiments, the progroup(s) R.sup.p in the prodrugs of structural formulae (I) and (Ia) are of the formula CR.sup.dR.sup.d-A-R.sup.3, where each R.sup.d is, independently of the other, selected from hydrogen, cyano, C(O)R.sup.e, C(O)OR.sup.e, C(O)NR.sup.eR.sup.e, C(OR.sup.e)(OR.sup.e), optionally substituted (C1-C20) alkyl, (C1-C20) perfluoroalkyl, optionally substituted (C7-C30) arylalkyl and optionally substituted 6-30 membered heteroarylalkyl, where each R.sup.e is, independently of the others, selected from hydrogen, alkyl (for example lower alkyl), aryl (for example phenyl or naphthyl, arylalkyl (for example benzyl), heteroaryl and heteroarylalkyl; A is selected from O, S and NR.sup.50, where R.sup.50 is selected from R.sup.d and cycloalkyl, or, alternatively, is taken together with R.sup.3 such that R.sup.50 and R.sup.3, together with nitrogen atom to which they are attached, form a three- to seven-membered ring; and R.sup.3 is a group that, together with A, metabolizes under the conditions of use to yield an intermediate group of the formula CR.sup.dR.sup.dAH, where R.sup.d and A are as previously defined. As mentioned above, compounds of structural formula (I) and (Ia) in which the R.sup.p groups are of the formula CR.sup.dR.sup.d-AH spontaneously hydrolyze in vivo to yield the active 2,4-pyrimidinediamine drug.

[0140] The mechanism by which the R.sup.3 group metabolizes to yield intermediate group CR.sup.dR.sup.d-A-H is not critical, and can be caused by, for example, hydrolysis under the acidic conditions of the stomach, and/or by enzymes present in the digestive tract and/or tissues or organs of the body. Indeed, the R.sup.3 group(s) can be selected to metabolize at a particular site within the body. For example, many esters are cleaved under the acidic conditions found in the stomach. Prodrugs designed to cleave chemically in the stomach to the active 2,4-pyrimidinediamine can employ progroups including such esters. Alternatively, the progroups may be designed to metabolize in the presence of enzymes such as esterases, amidases, lipolases, phosphatases including ATPases and kinase etc., to yield the intermediate group of formula CR.sup.dR.sup.d-A-H. Progroups including linkages capable of metabolizing in vivo to yield such an intermediate group are well-known, and include, by way of example and not limitation, ethers, thioethers, silylethers, silylthioethers, esters, thioesters, carbonates, thiocarbonates, carbamates, thiocarbamates, ureas, thioureas, carboxamides, etc. In some instances, a precursor group that is oxidized by oxidative enzymes such as, for example, cytochrome P450 of the liver, to a metabolizable group, can be selected.

[0141] The identity of the R.sup.3 group can also be selected so as to impart the prodrug with desirable characteristics. For example, lipophilic groups can be used to decrease water solubility and hydrophilic groups can be used to increase water solubility. In this way, prodrugs specifically tailored for selected modes of administration can be obtained. The R.sup.3 group can also be designed to impart the prodrug with other properties, such as, for example, improved passive intestinal absorption, improved transport-mediated intestinal absorption, protection against fast metabolism (slow-release prodrugs), tissue-selective delivery, passive enrichment in target tissues, targeting-specific transporters, etc. Groups capable of imparting prodrugs with these characteristics are well-known, and are described, for example, in Ettmayer et al., 2004, J. Med. Chem. 47(10:2393-2404), the disclosure of which is incorporated by reference. All of the various groups described in these references can be utilized in the prodrugs described herein.

[0142] In some embodiments, R.sup.3 is selected from R.sup.e, C(O)R.sup.f, C(O)NR.sup.fR.sup.f and SiR.sup.fR.sup.fR.sup.f, where the R.sup.f groups are selected so as to impart the prodrugs with desired bioavailability, cleavage and/or targeting properties. In a specific embodiment, the R.sup.f groups are selected to impart the prodrug with higher water-solubility than the underlying active 2,4-pyrimidinediamine drug. Thus, in some embodiments, the R.sup.f groups are selected such that they, taken together with the heteroatom or group to which they are bonded, are hydrophilic in character. Such hydrophilic groups can be charged or uncharged, as is well-known in the art. As specific examples, the R.sup.f groups may be selected from hydrogen, optionally substituted lower alkyl, optionally substituted lower heteroalkyl, optionally substituted lower cycloalkyl, optionally substituted lower heterocycloalkyl, optionally substituted (C6-C10) aryl, optionally substituted 5-10 membered heteroaryl, optionally substituted (C7-C18) arylalkyl and optionally substituted 6-18 membered heteroarylalkyl. The nature of any present substituents can vary widely, as is known in the art. In some embodiments any present substituents are, independently of one another, selected from R.sup.b, defined above.

[0143] In a specific embodiment, the progroups on the prodrugs of formula (I) and/or (Ia) are of the formula CR.sup.dR.sup.d-A-R.sup.3, where R.sup.3 is selected from (CH.sub.2).sub.iR.sup.b, C(O)R.sup.a, C(O)(CH.sub.2).sub.iR.sup.b, C(O)OR.sup.a and C(O)O(CH.sub.2).sub.iR.sup.b, where X, R.sup.a, R.sup.b and R.sup.d are as previously defined, and i is an integer ranging from 0 to 6. Specific, non-limiting, examples of exemplary water-solubility increasing progroups include by the way of example and not limitation, hydrophilic groups such as alkyl, arylk, arylalkyl, or cycloheteroalkyl groups substituted with one or more of an amine, alcohol, a carboxylic acid, a phosphorous acid, a sulfoxide, a sugar, an amino acid, a thiol, a polyol, a ether, a thioether and a quaternary amine salt.

[0144] One important class of progroups includes progroups that contain a phosphate group, for example, phosphate-containing progroups of the formula (R.sup.dR.sup.d).sub.yOP(O)(OH).sub.2, where R.sup.d is as defined above and y is an integer ranging from 1 to 3, typically 1 or 2. In a specific embodiment, each R.sup.d is, independently of the others, selected from hydrogen, substituted or unsubstituted lower alkyl, substituted or unsubstituted (C6-C14) aryl and substituted or unsubstituted (C7-C20) arylalkyl.

[0145] While not intending to be bound by any theory of operation, it is believed that such phosphate-containing progroups R.sup.p act as substrates for both alkaline and acid phosphatase enzymes, leading to their removal from the prodrugs under physiological conditions of use. As alkaline phosphatases are abundant in the digestive tract of humans, phosphate-containing progroups R.sup.P that can be cleaved in the presence of alkaline phosphatases are particularly suitable for formulating phosphate-containing prodrugs intended for oral administration. Specific examples of phosphate-containing progroups R.sup.P suitable for use in prodrugs intended for oral administration include, but are not limited to, groups of the formula (R.sup.dR.sup.d).sub.yOP(O)(OH).sub.2 in which each R.sup.d is, independently of the others, selected from hydrogen and unsubstituted lower alkanyl. Exemplary embodiments of such phosphate-containing progroups include, but are not limited to, CH.sub.2OP(O)(OH).sub.2 and CH.sub.2CH.sub.2OP(O)(OH).sub.2.

[0146] Although phosphate-containing prodrugs suitable for oral administration are of interest, skilled artisans will appreciate that prodrugs including phosphate-containing progroups R.sup.p can be administered via other routes of administration, as phosphatases are distributed throughout the body. For example, exemplary prodrug Compound 4 has been found to metabolize to the active drug Compound 1 in in vitro experiments carried out with rat plasma, as well as with rat hepatic and intestinal microsomal preparations, indicating that phosphatases are also present in plasma. Thus, the only requirement is that the particular phosphate-containing progroup R.sup.P selected should be removable under the conditions of intended use.

[0147] While not intending to be bound by any theory of operation, it is believed that when y is 1, phosphate-containing prodrugs, such as those according to structural formula (Ia), are metabolized to the active 2,4-pyrimidinediamine compound via the corresponding hydroxymethylamine. This metabolism is illustrated in FIG. 1A. Referring to FIG. 1A, removal of phosphoric acid from phosphate prodrug 16 via enzymatic hydrolysis yields the corresponding hydroxymethylamine 18, which undergoes hydrolysis in vivo to yield formaldehyde and active 2,4-pyrimidinediamine compound 10.

[0148] Referring to FIG. 1B, when y is 2, it is believed that in vivo hydrolysis of phosphate prodrug 26 yields active 2,4-pyrimidinediamine 10 and enol phosphate, which then hydrolyses in vivo to acetaldehyde and phosphoric acid.

[0149] Referring again to FIG. 1A, skilled artisan will appreciate that while hydroxymethylamine 18 metabolizes under physiological conditions to yield active 2,4-pyrimidinediamine compound 10, it is stable at pH 7 and can therefore be prepared and administered as a hydroxyalkyl-containing prodrug of active compound 10. Thus, in some embodiments of the prodrugs of structural formula (I), R.sup.p is a hydroxyalkyl-containing progroup of the formula CR.sup.dR.sup.dOH, where R.sup.d is as previously defined. In a specific exemplary embodiment, R.sup.p is CH.sub.2OH.

[0150] Still referring again to FIG. 1A, skilled artisans will also appreciate that phosphate prodrugs can be generated by in vivo hydrolysis of phosphate ester prodrugs, such as phosphate ester prodrugs 20 and/or by in vivo oxidation of phosphite prodrugs, such as phosphite prodrugs 24. Such phosphate ester and phosphite prodrugs can in turn be generated by either in vivo oxidation or hydrolysis of phosphite ester prodrugs such as phosphite ester prodrugs 22. The corresponding phosphate ester, phosphite and phosphite ester prodrugs of phosphate prodrug 26 are illustrated in FIG. 1B as compounds 30, 34 and 32, respectively. Thus, as will be appreciated by skilled artisans, prodrugs that include precursors of phosphates that can metabolize into phosphate groups in vivo are also included in the present invention.

[0151] In some embodiments of such prodrugs, the phosphorous-containing progroup R.sup.p comprises a phosphite group. A specific exemplary embodiment of such phosphite-containing prodrugs includes prodrug compounds in which the progroup R.sup.p is of the formula (CR.sup.dR.sup.d).sub.yOP(OH)(OH), where R.sup.d and y are as previously defined.

[0152] In other embodiments of such prodrugs, the phosphorous-containing progroup R.sup.p comprises an acyclic phosphate ester or phosphite ester group. Specific exemplary embodiments of such acyclic phosphate ester and phosphite ester prodrugs include progroups R.sup.p of the formula (CR.sup.dR.sup.d).sub.yOP(O)(OH)(OR.sup.e), (CR.sup.dR.sup.d).sub.yOP(O)(OR.sup.e).sub.2, (CR.sup.dR.sup.d).sub.yOP(OH)(OR.sup.e) and (CR.sup.dR.sup.d).sub.yOP(OR.sup.e).sub.2, where R.sup.e is selected from substituted or unsubstituted lower alkyl, substituted or unsubstituted (C6-C14) aryl (e.g., phenyl, naphthyl, 4-lower alkoxyphenyl, 4-methoxyphenyl), substituted or unsubstituted (C7-C20) arylalkyl (e.g., benzyl, 1-phenylethan-1-yl, 2-phenylethan-1-yl), (CR.sup.dR.sup.d).sub.yOR.sup.f, (CR.sup.dR.sup.d).sub.yOC(O)R.sup.f, (CR.sup.dR.sup.d).sub.yOC(O)OR.sup.f, (CR.sup.dR.sup.d).sub.ySC(O)R.sup.f, (CR.sup.dR.sup.d).sub.ySC(O)OR.sup.f, (CR.sup.dR.sup.d), NHC(O)R.sup.f, (CR.sup.dR.sup.d).sub.yNHC(O)OR.sup.f and Si(R.sup.d).sub.3, wherein each R.sup.f is, independently of the others, selected from hydrogen, unsubstituted or substituted lower alkyl, substituted or unsubstituted (C6-C14) aryl, and substituted or unsubstituted (C7-C20) arylalkyl, and R.sup.d and y are as previously defined.

[0153] In still other embodiments, phosphorous-containing prodrugs that include phosphate precursors are prodrugs in which the phosphorous-containing progroup R.sup.p comprises a cyclic phosphate ester of the formula

##STR00017##

where each R9 is, independently of the others, selected from hydrogen and lower alkyl; each R.sup.h is, independently of the others, selected from hydrogen, substituted or unsubstituted lower alkyl, substituted or unsubstituted lower cycloheteroalkyl, substituted or unsubstituted (C6-C14) aryl, substituted or unsubstituted (C7-C20) arylalkyl and substituted or unsubstituted 5-14 membered heteroaryl; z is an integer ranging from 0 to 2; and R.sup.d and y are as previously defined.

[0154] In still other embodiments, phosphorous-containing prodrugs that include phosphate precursors are prodrugs in which the phosphorous-containing progroup R.sup.P comprises a cyclic phosphite ester of the formula

##STR00018##

where R.sup.g, R.sup.h, R.sup.d, y and z are as previously defined.

[0155] In some embodiments, the substituents R.sup.h on such cyclic phosphate ester and phosphite ester prodrugs are selected such that the progroup is metabolized in vitro by esterase enzymes. Specific examples of such phosphate ester and phosphite ester progroups include those in which each R.sup.h is, independently of the others, selected from hydrogen, lower alkyl, methyl, ethyl and propyl. In some embodiments, such progroups are selected from

##STR00019## ##STR00020##

[0156] Many of these phosphate esters and phosphite esters are acid label and, when administered orally, metabolize to the corresponding phosphates and phosphites under the acidic conditions of the stomach and/or gut.

[0157] Thus, in the phosphorous-containing prodrugs described herein, the identity of the particular phosphorous-containing progroups R.sup.p employed can be selected to tailor the prodrugs for particular modes of delivery, etc.

[0158] The suitability of any particular progroup R.sup.p for a desired mode of administration can be confirmed in biochemical assays. For example, if a prodrug is to be administered by injection into a particular tissue or organ, and the identities of the various phosphatases expressed in the tissue or organ are known, the particular prodrug can be tested for metabolism in biochemical assays with the isolated phosphatase(s). Alternatively, the particular prodrug can be tested for metabolism to the active 2,4-pyrimidinediamine compound with tissue and/or organ extracts. Using tissue and/or organ extracts can be of particular convenience when the identity(ies) of the phosphatases expressed in the target tissues or organs are unknown, or in instances when the isolated phosphatases are not conveniently available. Skilled artisans will be able to readily select progroups R.sup.p having metabolic properties (such as kinetics) suitable for particular applications using such in vitro tests. Of course, specific prodrugs could also be tested for suitable metabolism in in vitro animal models.

[0159] In some embodiments, the prodrugs are prodrugs according to structural formula (I) or (Ia) that have one or more features selected from: [0160] (i) R.sup.5 is fluoro; [0161] (ii) R.sup.2 is a phenyl optionally substituted with one or more of the same or different R.sup.8 groups; [0162] (iii) R.sup.2 is 3,4,5-tri(loweralkoxy)phenyl; [0163] (iv) R.sup.2 is 3,4,5-trimethoxyphenyl; [0164] (v) Y or Y.sup.1 is O; Z.sup.1 is CH, Z.sup.2 is N; R.sup.17 and R.sup.18 are each methyl; and R.sup.19 and R.sup.20 are taken together to form an oxogroup; and [0165] (vi) R.sup.p is a hydroxyalkyl-containing progroup of the formula CH.sub.2OH, or a phosphate-containing progroup of the formula (CR.sup.dR.sup.d).sub.yOP(O)(OH).sub.2, or a phosphate ester, phosphite or phosphite ester analog thereof, wherein y is 1 or 2 and each R.sup.d is, independently of the others, selected from hydrogen and unsubstituted lower alkyl, or [0166] (vii) R.sup.p is selected from CH.sub.2OH, CH.sub.2SH, CH.sub.2NH.sub.2, CH.sub.2NHR.sup.50, CH.sub.2N(R.sup.50).sub.2, CH.sub.2-A-R.sup.f, CH.sub.2-A-C(O)R.sup.f, CH.sub.2-A-C(O)OR.sup.f and CH.sub.2-A-C(O)NR.sup.fR.sup.f, where A, R.sup.50 and R.sup.f are as previously defined.

[0167] In some embodiments, the prodrugs of structural formulae (I) and (Ia) have two or three of the above-delineated features. In one specific embodiment, the prodrugs have features (i), (iii) and (v). In another specific embodiment, the prodrugs have features (i), (iv) and (v). In still another specific embodiment, the prodrugs have features (i), (iii), (v) and (vi) or (vii). In still another specific embodiment, the prodrugs have features (i), (iv), (v) and (vi) or (vii). In still another specific embodiment, R.sup.p is a phosphate-containing progroup of the formula (CR.sup.dR.sup.d).sub.yOP(O)(OH).sub.2.

[0168] In all of the compounds described herein that include substituent alternatives that may be substituted, such as, for example, some of the substituent alternatives delineated for R.sup.d, R.sup.e, R.sup.f, R.sup.g, R.sup.h, R.sup.i and R.sup.j, the substitutions are typically, independently of one another, selected from amongst the R.sup.b groups described in connection with structural formula (I). In a specific embodiment, any present substitutions are, independently of one another, selected from hydroxyl, lower alkoxy, (C6-C14) aryloxy, lower alkoxyalkyl, methoxymethyl, methoxyethyl, ethoxymethyl, ethoxyethyl and halogen.

[0169] Those of skill in the art will appreciate that many of the prodrugs described herein, as well as the various prodrug species specifically described and/or illustrated herein, may exhibit the phenomena of tautomerism, conformational isomerism, geometric isomerism and/or optical isomerism. For example, the prodrugs may include one or more chiral centers and/or double bonds and as a consequence may exist as stereoisomers, such as double-bond isomers (i.e., geometric isomers), enantiomers and diasteromers and mixtures thereof, such as racemic mixtures. As another example, the prodrugs may exist in several tautomeric forms, including the enol form, the keto form and mixtures thereof. As the various compound names, formulae and drawings within the specification and claims can represent only one of the possible tautomeric, conformational isomeric, optical isomeric or geometric isomeric forms, it should be understood that the invention encompasses any tautomeric, conformational isomeric, optical isomeric and/or geometric isomeric forms of the prodrugs having one or more of the utilities described herein, as well as mixtures of these various different isomeric forms. In cases of limited rotation around the 2,4-pryimidinediamine moiety, atrop isomers are also possible and are also specifically included in the compounds of the invention.

[0170] Moreover, skilled artisans will appreciate that when lists of alternative substituents include members which, owing to valency requirements or other reasons, cannot be used to substitute a particular group, the list is intended to be read in context to include those members of the list that are suitable for substituting the particular group. For example, skilled artisans will appreciate that while all of the listed alternatives for R.sup.b can be used to substitute an alkyl group, certain of the alternatives, such as O, cannot be used to substitute a phenyl group. It is to be understood that only possible combinations of substituent-group pairs are intended.

[0171] The prodrugs described herein may be identified by either their chemical structure or their chemical name. When the chemical structure and the chemical name conflict, the chemical structure is determinative of the identity of the specific prodrug.

[0172] Depending upon the nature of the various substituents, the prodrugs described herein may be in the form of salts. Such salts include salts suitable for pharmaceutical uses (pharmaceutically-acceptable salts), salts suitable for veterinary uses, etc. Such salts may be derived from acids or bases, as is well-known in the art.

[0173] In one embodiment, the salt is a pharmaceutically acceptable salt. Generally, pharmaceutically acceptable salts are those salts that retain substantially one or more of the desired pharmacological activities of the parent compound and which are suitable for administration to humans. Pharmaceutically acceptable salts include acid addition salts formed with inorganic acids or organic acids. Inorganic acids suitable for forming pharmaceutically acceptable acid addition salts include, by way of example and not limitation, hydrohalide acids (e.g., hydrochloric acid, hydrobromic acid, hydriodic, etc.), sulfuric acid, nitric acid, phosphoric acid, and the like. Organic acids suitable for forming pharmaceutically acceptable acid addition salts include, by way of example and not limitation, acetic acid, trifluoroacetic acid, propionic acid, hexanoic acid, cyclopentanepropionic acid, glycolic acid, oxalic acid, pyruvic acid, lactic acid, malonic acid, succinic acid, malic acid, maleic acid, fumaric acid, tartaric acid, citric acid, palmitic acid, benzoic acid, 3-(4-hydroxybenzoyl) benzoic acid, cinnamic acid, mandelic acid, alkylsulfonic acids (e.g., methanesulfonic acid, ethanesulfonic acid, 1,2-ethane-disulfonic acid, 2-hydroxyethanesulfonic acid, etc.), arylsulfonic acids (e.g., benzenesulfonic acid, 4-chlorobenzenesulfonic acid, 2-naphthalenesulfonic acid, 4-toluenesulfonic acid, camphorsulfonic acid, etc.), 4-methylbicyclo[2.2.2]-oct-2-ene-1-carboxylic acid, glucoheptonic acid, 3-phenylpropionic acid, trimethylacetic acid, tertiary butylacetic acid, lauryl sulfuric acid, gluconic acid, glutamic acid, hydroxynaphthoic acid, salicylic acid, stearic acid, muconic acid, and the like.

[0174] Pharmaceutically acceptable salts also include salts formed when an acidic proton present in the parent compound is either replaced by a metal ion (e.g., an alkali metal ion, an alkaline earth metal ion or an aluminum ion) or coordinates with an organic base (e.g., ethanolamine, diethanolamine, triethanolamine, N-methylglucamine, morpholine, piperidine, dimethylamine, diethylamine, etc.).

[0175] The prodrugs described herein, as well as the salts thereof, may also be in the form of hydrates, solvates and N-oxides, as are well-known in the art. Unless specifically indicated otherwise, the expression prodrug is intended to encompass such salts, hydrates, solvates and/or N-oxides. Specific exemplary salts include, but are not limited to, mono- and di-sodium salts, mono- and di-potassium salts, mono- and di-lithium salts, mono- and di-alkylamino salts, mono-magnesium salts, mono-calcium salts and ammonium salts.

6.3 Methods of Synthesis

[0176] The prodrugs described herein, as well as intermediates therefor, may be synthesized via a variety of different synthetic routes using commercially available starting materials and/or starting materials prepared by conventional synthetic methods. Suitable exemplary methods that may be routinely used and/or adapted to synthesize active 2,4-pyrimidinediamine compounds can be found in U.S. Pat. No. 5,958,935, U.S. application Ser. No. 10/355,543 filed Jan. 31, 2003 (US2004/0029902A1), international application Serial No. PCT/US03/03022 filed Jan. 31, 2003 (WO 03/063794), U.S. application Ser. No. 10/631,029 filed Jul. 29, 2003 (______), international application Serial No. PCT/US03/24087 (WO2004/014382), U.S. application Ser. No. 10/903,263 filed Jul. 30, 2004 (US2005/0234049), and international application Serial No. PCT/US2004/24716 (______), the disclosures of which are incorporated herein by reference. These active 2,4-pyrimidinediamine compounds can be used as starting materials to synthesize the prodrugs. Specific examples describing the synthesis of phosphate prodrug Compound 4, as well as a synthetic intermediate therefor, are provided in the Examples section. All of the prodrugs described herein may be synthesized by routine adaptation of this method.

[0177] For example, some embodiments of prodrugs according to structural formula (I) and/or (Ia) can be prepared by reacting the corresponding active 2,4-pyrimidinediamine (i.e., compounds according to structural formulae (I) and/or (Ia) in which each R.sup.p is hydrogen) with an aldehyde or a ketone to give an -hydroxymethyl amine, which can then be reacted with an electrophile to yield a prodrug. An exemplary synthesis of this type is illustrated in Scheme (I), below:

##STR00021##

[0178] In Scheme (I), Y.sup.1, Z.sup.1, Z.sup.2, R.sup.2, R.sup.5, R.sup.17, R.sup.18, R.sup.19 and R.sup.20 are as defined for structural formula (I) or (Ia). R.sup.3 and R.sup.d are as defined in the text, supra. According to Scheme (I), active 2,4-pyrimidinediamine 10 is reacted with ketone 12 to yield a mixture of four products: unreacted starting material 10 (not illustrated) and compounds 14a, 14b and 14c. At this stage, the products can be isolated from one another using standard chromatographic techniques. Reaction with electropholic R.sup.3 yields prodrugs 15a, 15b and 15c.

[0179] As illustrated above, -hydroxymethylamines 14a, 14b and 14c can be converted into a variety of different types of prodrugs 15a, 15b and 15c. For example, the -hydroxymethylamines can be reacted with an alcohol in the presence of a strong acid catalyst, or a carbon-bearing halide (e.g., CH.sub.3Br), to yield the corresponding ether derivatives (e.g., compounds in which R.sup.3 is R.sup.f, where R.sup.f is as previously defined).

[0180] Reacting -hydroxymethylamines 14a, 14b and 14c with a carboxylic acid in the presence of a strong acid catalyst or a carboxylic acid anhydride or a carboxylic acid halide (e.g. with an appropriate acid scavenger) yields the corresponding ester derivatives (e.g., compounds in which R.sup.3 is C(O)R.sup.f, where R.sup.f is as defined above).

[0181] Reaction of -hydroxymethylamines 14a, 14b and 14c with a haloformate ester (e.g., C1-C(O)OCH.sub.3) yields the corresponding carbonate derivatives (e.g., compounds in which R.sup.3 is C(O)OR.sup.f, where R.sup.f is as previously defined).

[0182] Reaction of -hydroxymethylamines 14a, 14b and 14c with a haloformamide (e.g., C1-C(O)N(CH.sub.3).sub.2) yields the corresponding carbamate or urethane derivatives (e.g., compounds in which R.sup.3 is C(O)NR.sup.fR.sup.f, where R.sup.f is as previously defined).

[0183] As will be recognized by skilled artisans, other hydroxyl protecting groups could also be used, including, for example, the various different hydroxyl protecting groups described in Green & Wuts, Protective Groups in Organic Chemistry,2d Edition, John Wiley & Sons, New York, pp. 10-142, the disclosure of which is incorporated herein by reference.

[0184] Alternatively, prodrugs according to structural formulae (I) and (Ia) can be synthesized by nucleophilic substitution of the corresponding phosphate esters. An example of this synthetic route is illustrated in Scheme (II), below:

##STR00022##

[0185] According to Scheme (II), active 2,4-pyrimidinediamine 10 is reacted with di-tert-butyl chloromethylphosphate 13 in the presence of cesium carbonate to yield a mixture of four products: unreacted starting material 10 (not illustrated) and phosphate esters 17a, 17b and 17c, which are themselves prodrugs as described herein. When R.sup.2 is 3,4,5-trimethoxyphenyl phosphate ester 17a is the major product. Reaction of this phosphate ester 17a with R.sup.3-AH (where A is O, S, or NR.sup.50), yields prodrug 19. The minor phosphate esters 17b and 17c can be similarly reacted to yield the corresponding prodrugs.

[0186] Di-tert-butyl chloromethyl phosphate 13 can be prepared from di-tert-butyl phosphate as illustrated in Scheme (III), below:

##STR00023##

[0187] According to Scheme (III), di-tert-butyl phosphate 9 is obtained from the corresponding di-tert-butyl phosphite 7 as described in Krise et al., 1990, J. Med. Chem. 42:3793-3794. Reaction of phosphate 9 with chloromethyl chlorosulfate 11 (available from Synergetica, Inc., Sicklerville, N.J. 08081) as described in Mantyla et al., 2002, Tet. Lett. 43:3793-3794 yields di-tert-butyl chloromethyl phosphate 13, which can be used in Scheme (II), above, crude without purification.

[0188] Although the Schemes illustrated above depict the synthesis of prodrugs that include a single progroup, prodrugs having a plurality of progroups could be obtained by adjusting the number of equivalents of reagent 12 or 13 used.

[0189] As another alternative to Scheme (I), hydroxymethylamine 14a can be prepared in a two-step process by first reacting active 2,4-pyrimidinediamine 10 with a bis functional electrophile, such as, for example, chloro-iodomethane (ICH.sub.2Cl), to yield a chloro-methyl intermediate, which can then be hydroxylated by reaction with basic hydroxide or reacted with various nucleophilic reagents such as alkoxides, amines or sulfide to make R.sup.p. Specific conditions for carrying out reactions of this type that can be used to synthesize the prodrugs described herein, for example, in Bansal et al., 1981, J. Pharm. Sci. 70(8):850-854 and Bansal et al., 1981, J. Pharm. Sci. 70(8):855-857, the disclosures of which are incorporated herein by reference.

[0190] An exemplary synthetic route that can be used to synthesize an exemplary phosphate prodrug 16 according to structural formula (Ia) is illustrated in Scheme (IV), below. This method may be routinely adapted to synthesize the full range of phosphate prodrugs described herein.

##STR00024##

[0191] In Scheme (IV), Y.sup.1, Z.sup.1, Z.sup.2, R.sup.2, R.sup.5, R.sup.17, R.sup.18, R.sup.19 and R.sup.20 are as defined for structural formula (I) or (Ia). According to Scheme (IV), active 2,4-pyrimidinediamine 10 is reacted with di-tert-butyl chloromethylphosphate 13 in the presence of cesium carbonate to yield a mixture of four products: unreacted starting material 10 (not illustrated) and compounds 17a, 17b and 17c. When R.sup.2 is 3,4,5-trimethyoxyphenyl, compound 17a is the major product. At this stage, the major product can be isolated from the minor products using standard chromatographic techniques. Removal of the tert-butyl groups yields a mixture of desired product 16 and impurities 18 and 10. The desired product 16 can be isolated using standard techniques.

[0192] An alternative method of obtaining phosphate prodrug 16 is illustrated in Scheme (V); below.

##STR00025##

[0193] According to Scheme (V), the reaction of active 2,4-pyrimidinediamine 10 again yields a mixture of four products: unreacted pyrimidinediamine 10 (not illustrated) major product 17a and minor products 17b and 17c. Major product 17a can be isolated via crystallization (see the Examples section for suitable conditions), dissolved in a mixture of acetic acid and water (4:1 AcOH:H.sub.2O) and heated to 65 C. for approximately 3 hr to yield phosphate prodrug 16 as the major product.

[0194] Although Schemes (IV) and (V) illustrate the synthesis of a phosphate prodrug in which the phosphate progroup is CH.sub.2OP(O)(OH).sub.2, skilled artisans will appreciate that phosphate prodrugs including other phosphate progroups could be readily obtained according to the same methods by using the appropriate reagent 13. Phosphate ester prodrugs, phosphite prodrugs and phosphite ester prodrugs can also be synthesized via routine adaptation of the methods using the appropriate phosphate ester, phosphite and phosphite ester halides 13. Exemplary methods for synthesizing cyclic phosphate ester prodrugs, which can be used as prodrugs in the various methods described herein, or converted into phosphate prodrugs, are illustrated in FIG. 3. Moreover, while Schemes (I) and (III) depict compound 16 as being the desired product, prodrugs having progroups at other positions within the prodrug molecule could be readily obtained by isolating, for example minor product 17a or 17b and/or by adjusting the number of equivalents of reagent 13 used.

[0195] Referring to FIG. 3, diols 21 are converted to the corresponding cyclic phosphates 23 using literature procedures as depicted. Cyclic phosphates 23 are converted to the corresponding chloromethyl phosphate esters 25 in any of the three ways depicted. Compound 1 is converted to cyclic phosphate ester derivatives 27, 29, and 31, via addition of 25 under conditions as previously described for the synthesis of compounds 17a-c. Cyclic phosphate ester derivatives 27, 29, and 31, are converted to the corresponding phosphate derivatives via treatment under acidic conditions as described for the synthesis of compound 16, or via hydrogenation using, for example, palladium catalyst.

[0196] Skilled artisans will recognize that in some instances, the active 2,4-pyrimidinediamine compounds used as starting materials may include functional groups that require protection during synthesis. The exact identity of any protecting group(s) used will depend upon the identity of the functional group being protected, and will be apparent to these of skill in the art. Guidance for selecting appropriate protecting groups, as well as synthetic strategies for their attachment and removal, may be found, for example, in Greene & Wuts, Protective Groups in Organic Synthesis, 3d Edition, John Wiley & Sons, Inc., New York (1999) and the references cited therein (hereinafter Greene & Wuts).

6.4 Inhibition of Fc Receptor Signal Cascades

[0197] Many of the prodrugs described herein, and in particular the prodrugs according to structural formulae (I) and (Ia), metabolize to active 2,4-pyrimidinediamine compounds that inhibit Fc receptor signaling cascades that lead to, among other things, degranulation of cells. As a specific example, these active compounds inhibit the FcRI and/or FcRI signal cascades that lead to degranulation of immune cells such as neutrophil, eosinophil, mast and/or basophil cells. Both mast and basophil cells play a central role in allergen-induced disorders, including, for example, allergic rhinitis and asthma. Upon exposure allergens, which may be, among other things, pollen or parasites, allergen-specific IgE antibodies are synthesized by B-cells activated by IL-4 (or IL-13) and other messengers to switch to IgE class specific antibody synthesis. These allergen-specific IgEs bind to the high affinity FcRI. Upon binding of antigen, the FcR1-bound IgEs are cross-linked and the IgE receptor signal transduction pathway is activated, which leads to degranulation of the cells and consequent release and/or synthesis of a host of chemical mediators, including histamine, proteases (e.g., tryptase and chymase), lipid mediators such as leukotrienes (e.g., LTC4), platelet-activating factor (PAF) and prostaglandins (e.g., PGD2) and a series of cytokines, including TNF-, IL-4, IL-13, IL-5, IL-6, IL-8, GMCSF, VEGF and TGF-. The release and/or synthesis of these mediators from mast and/or basophil cells accounts for the early and late stage responses induced by allergens, and is directly linked to downstream events that lead to a sustained inflammatory state.

[0198] The molecular events in the FcRI signal transduction pathway that lead to release of preformed mediators via degranulation and release and/or synthesis of other chemical mediators are well-known. The FcRI is a heterotetrameric receptor composed of an IgE-binding alpha-subunit, a beta subunit, and two gamma subunits (gamma homodimer). Cross-linking of FcRI-bound IgE by multivalent binding agents (including, for example IgE-specific allergens or anti-IgE antibodies or fragments) induces the rapid association and activation of the Src-related kinase Lyn. Lyn phosphorylates immunoreceptor tyrosine-based activation motifs (ITAMS) on the intracellular beta and gamma subunits, which leads to the recruitment of additional Lyn to the beta subunit and Syk kinase to the gamma homodimer.

[0199] These receptor-associated kinases, which are activated by intra- and intermolecular phosphorylation, phosphorylate other components of the pathway, such as the Btk kinase, LAT, and phospholipase C-gamma PLC-gamma). Activated PLC-gamma initiates pathways that lead to protein kinase C activation and Ca.sup.2+ mobilization, both of which are required for degranulation. FcR1 cross-linking also activates the three major classes of mitogen activated protein (MAP) kinases, i.e. ERK1/2, JNK1/2, and p38. Activation of these pathways is important in the transcriptional regulation of proinflammatory mediators, such as TNF- and IL-6, as well as the lipid mediator leukotriene C4 (LTC4).

[0200] The FcRI signaling cascade is believed to share some common elements with the FcRI signaling cascade. Importantly, like FcRI, the FcRI includes a gamma homodimer that is phosphorylated and recruits Syk, and like FcRI, activation of the FcRI signaling cascade leads to, among other things, degranulation. Other Fc receptors that share the gamma homodimer, and which can be regulated by the active 2,4-pyrimidinediamine compounds include, but are not limited to, FcRI and FcRIII.

[0201] In vitro and cellular assays suitable for confirming the activity of a particular 2,4-pyrimidinediamine compound are described in detail in U.S. application Ser. No. 10/355,543 filed Jan. 31, 2003 (US2004/0029902A1), international application Serial No. PCT/US03/03022 filed Jan. 31, 2003 (WO 03/063794), U.S. application Ser. No. 10/631,029 filed Jul. 29, 2003 (______), international application Serial No. PCT/US03/24087 (WO2004/014382), U.S. application Ser. No. 10/903,263 filed Jul. 30, 2004 (US2005/0234049), and international application Serial No. PCT/US2004/24716 (______).

[0202] The ability of a particular prodrug to metabolize to an active 2,4-pyrimidinediamine compound under the desired conditions of use can be confirmed in in vitro and/or in vivo assays, as previously described.

6.5 Uses and Compositions

[0203] As previously discussed, the prodrugs described herein, such as the prodrugs according to structural formulae (I) and (Ia) metabolize when administered to animals and humans into active compounds that inhibit Fc receptor signaling cascades, especially those Fc receptors including a gamma homodimer, such as the FcRI and/or FcRI signaling cascades, that lead to, among other things, the release and/or synthesis of chemical mediators from cells, either via degranulation or other processes. As also discussed, the active compounds are also potent inhibitors of Syk kinase. As a consequence of these activities, prodrugs of these active compounds may be used in a variety of in vitro, in vivo and ex vivo contexts to regulate or inhibit Syk kinase, signaling cascades in which Syk kinase plays a role, Fc receptor signaling cascades, and the biological responses effected by such signaling cascades. For example, in one embodiment, the prodrugs may be used to inhibit Syk kinase, either in vitro or in vivo, in virtually any cell type expressing Syk kinase. They may also be used to regulate signal transduction cascades in which Syk kinase plays a role. Such Syk-dependent signal transduction cascades include, but are not limited to, the FcRI, FcRI, FcRIII, BCR and integrin signal transduction cascades. The prodrugs may also be used in vitro or in vivo to regulate, and in particular inhibit, cellular or biological responses effected by such Syk-dependent signal transduction cascades. Such cellular or biological responses include, but are not limited to, respiratory burst, cellular adhesion, cellular degranulation, cell spreading, cell migration, cell aggregation, phagocytosis, cytokine synthesis and release, cell maturation and Ca.sup.2+ flux. Importantly, the prodrugs may be used to inhibit Syk kinase in vivo as a therapeutic approach towards the treatment or prevention of diseases mediated, either wholly or in part, by a Syk kinase activity. Non-limiting examples of Syk kinase mediated diseases that may be treated or prevented with the prodrugs are those discussed in more detail, below.

[0204] In another embodiment, the prodrugs may be used to regulate or inhibit the Fc receptor signaling cascades and/or FcRI- and/or FcRI-mediated degranulation as a therapeutic approach towards the treatment or prevention of diseases characterized by, caused by and/or associated with the release or synthesis of chemical mediators of such Fc receptor signaling cascades or degranulation. Such treatments may be administered to animals in veterinary contexts or to humans. Diseases that are characterized by, caused by or associated with such mediator release, synthesis or degranulation, and that can therefore be treated or prevented with the active compounds include, by way of example and not limitation, atopy or anaphylactic hypersensitivity or allergic reactions, allergies (e.g., allergic conjunctivitis, allergic rhinitis, atopic asthma, atopic dermatitis and food allergies), low grade scarring (e.g., of scleroderma, increased fibrosis, keloids, post-surgical scars, pulmonary fibrosis, vascular spasms, migraine, reperfusion injury and post myocardial infarction), diseases associated with tissue destruction (e.g., of COPD, cardiobronchitis and post myocardial infarction), diseases associated with tissue inflammation (e.g., irritable bowel syndrome, spastic colon and inflammatory bowel disease), inflammation and scarring.

[0205] Recent studies have shown that activation of platelets by collagen is mediated through the same pathway used by immune receptors, with an immunoreceptor tyronsine kinase motif on the FcR playing a pivotal role (Watson & Gibbons, 1998, Immunol. Today 19:260-264), and also that FcR plays a pivotal role in the generation of neointimal hyperplasia following balloon injury in mice, most likely through collagen-induced activation of platelets and leukocyte recruitment (Konishi et al., 2002, Circulation 105:912-916). Thus, the prodrugs described herein can also be used to inhibit collagen-induced platelet activation and to treat or prevent diseases associated with or caused by such platelet activation, such as, for example, intimal hyperplasia and restenosis following vascular injury.

[0206] In addition to the myriad diseases discussed above, cellular and animal empirical data confirm that the active 2,4-pyrimidinediamine compounds described in U.S. application Ser. No. 10/631,029 filed Jul. 29, 2003 (______), international application Serial No. PCT/US03/24087 (WO2004/014382), U.S. application Ser. No. 10/903,263 filed Jul. 30, 2004 (US2005/0234049), and international application Serial No. PCT/US2004/24716 (______) are also useful for the treatment or prevention of autoimmune diseases, as well as the various symptoms associated with such diseases. Thus, prodrugs of these active compounds are useful for treating or preventing such diseases and/or symptoms. The types of autoimmune diseases that may be treated or prevented with such prodrugs generally include those disorders involving tissue injury that occurs as a result of a humoral and/or cell-mediated response to immunogens or antigens of endogenous and/or exogenous origin. Such diseases are frequently referred to as diseases involving the nonanaphylactic (i.e., Type II, Type III and/or Type IV) hypersensitivity reactions.

[0207] As discussed previously, Type I hypersensitivity reactions generally result from the release of pharmacologically active substances, such as histamine, from mast and/or basophil cells following contact with a specific exogenous antigen. As mentioned above, such Type I reactions play a role in numerous diseases, including allergic asthma, allergic rhinitis, etc.

[0208] Type II hypersensitivity reactions (also referred to as cytotoxic, cytolytic complement-dependent or cell-stimulating hypersensitivity reactions) result when immunoglobulins react with antigenic components of cells or tissue, or with an antigen or hapten that has become intimately coupled to cells or tissue. Diseases that are commonly associated with Type II hypersensitivity reactions include, but are not limited, to autoimmune hemolytic anemia, erythroblastosis fetalis and Goodpasture's disease.

[0209] Type III hypersensitivity reactions, (also referred to as toxic complex, soluble complex, or immune complex hypersensitivity reactions) result from the deposition of soluble circulating antigen-immunoglobulin complexes in vessels or in tissues, with accompanying acute inflammatory reactions at the site of immune complex deposition. Non-limiting examples of prototypical Type III reaction diseases include the Arthus reaction, rheumatoid arthritis, serum sickness, systemic lupus erythematosis, certain types of glomerulonephritis, multiple sclerosis and bullous pemphingoid.

[0210] Type IV hypersensitivity reactions (frequently called cellular, cell-mediated, delayed, or tuberculin-type hypersensitivity reactions) are caused by sensitized T-lymphocytes which result from contact with a specific antigen. Non-limiting examples of diseases cited as involving Type IV reactions are contact dermatitis and allograft rejection.

[0211] Autoimmune diseases associated with any of the above nonanaphylactic hypersensitivity reactions may be treated or prevented with the prodrugs according to structural formulae (I) and (Ia). In particular, the methods may be used to treat or prevent those autoimmune diseases frequently characterized as single organ or single cell-type autoimmune disorders including, but not limited to: Hashimoto's thyroiditis, autoimmune hemolytic anemia, autoimmune atrophic gastritis of pernicious anemia, autoimmune encephalomyelitis, autoimmune orchitis, Goodpasture's disease, autoimmune thrombocytopenia, sympathetic ophthalmia, myasthenia gravis, Graves' disease, primary biliary cirrhosis, chronic aggressive hepatitis, ulcerative colitis and membranous glomerulopathy, as well as those autoimmune diseases frequently characterized as involving systemic autoimmune disorder, which include but are not limited to: systemic lupus erythematosis (SLE), rheumatoid arthritis, Sjogren's syndrome, Reiter's syndrome, polymyositis-dermatomyositis, systemic sclerosis, polyarteritis nodosa, multiple sclerosis and bullous pemphigoid.

[0212] It will be appreciated by skilled artisans that many of the above-listed autoimmune diseases are associated with severe symptoms, the amelioration of which provides significant therapeutic benefit even in instances where the underlying autoimmune disease may not be ameliorated. Many of these symptoms, as well as their underlying disease states, result as a consequence of activating the FcR signaling cascade in monocyte cells. As the prodrugs of structural formulae (I) and (Ia) metabolize to 2,4-pyrimidinediamine compounds that are potent inhibitors of such FcR signaling in monocytes and other cells, the methods find use in the treatment and/or prevention of myriad adverse symptoms associated with the above-listed autoimmune diseases.

[0213] As a specific example, rheumatoid arthritis (RA) typically results in swelling, pain, loss of motion and tenderness of target joints throughout the body. RA is characterized by chronically inflamed synovium that is densely crowded with lymphocytes. The synovial membrane, which is typically one cell layer thick, becomes intensely cellular and assumes a form similar to lymphoid tissue, including dendritic cells, T-, B- and NK cells, macrophages and clusters of plasma cells. This process, as well as a plethora of immunopathological mechanisms including the formation of antigen-immunoglobulin complexes, eventually result in destruction of the integrity of the joint, resulting in deformity, permanent loss of function and/or bone erosion at or near the joint. The methods may be used to treat or ameliorate any one, several or all of these symptoms of RA. Thus, in the context of RA, the methods are considered to provide therapeutic benefit (discussed more generally, infra) when a reduction or amelioration of any of the symptoms commonly associated with RA is achieved, regardless of whether the treatment results in a concomitant treatment of the underlying RA and/or a reduction in the amount of circulating rheumatoid factor (RF).

[0214] The American College of Rheumatology (ACR) has developed criteria for defining improvement and clinical remission in RA. Once such parameter, the ACR20 (ACR criteria for 20% clinical improvement), requires a 20% improvement in the tender and swollen joint count, as well as a 20% improvement in 3 of the following 5 parameters: patient's global assessment, physician's global assessment, patient's assessment of pain, degree of disability, and level of acute phase reactant. These criteria have been expanded for 50% and 70% improvement in ACR50 and ACR70, respectively. Other criteria includes Paulu's criteria and radiographic progression (e.g. Sharp score).

[0215] In some embodiments, therapeutic benefit in patients suffering from RA is achieved when the patient exhibits an ARC20. In specific embodiments, ARCs of ARC50 or even ARC70 may be achieved.

[0216] Systemic lupus erythematosis (SLE) is typically associated with symptoms such as fever, joint pain (arthralgias), arthritis, and serositis (pleurisy or pericarditis). In the context of SLE, the methods are considered to provide therapeutic benefit when a reduction or amelioration of any of the symptoms commonly associated with SLE are achieved, regardless of whether the treatment results in a concomitant treatment of the underlying SLE.

[0217] Multiple sclerosis (MS) cripples the patient by disturbing visual acuity; stimulating double vision; disturbing motor functions affecting walking and use of the hands; producing bowel and bladder incontinence; spasticity; and sensory deficits (touch, pain and temperature sensitivity). In the context of MS, the methods are considered to provide therapeutic benefit when an improvement or a reduction in the progression of any one or more of the crippling effects commonly associated with MS is achieved, regardless of whether the treatment results in a concomitant treatment of the underlying MS.

[0218] When used to treat or prevent such diseases, the prodrugs described herein may be administered singly, as mixtures of one or more prodrugs or in mixture or combination with other agents useful for treating such diseases and/or the symptoms associated with such diseases. The prodrugs may also be administered in mixture or in combination with agents useful to treat other disorders or maladies, such as steroids, membrane stabilizers, 5LO inhibitors, leukotriene synthesis and receptor inhibitors, inhibitors of IgE isotype switching or IgE synthesis, IgG isotype switching or IgG synthesis, 1-agonists, tryptase inhibitors, aspirin, COX inhibitors, methotrexate, anti-TNF drugs, retuxin, PD4 inhibitors, p38 inhibitors, PDE4 inhibitors, and antihistamines, to name a few. The prodrugs may be administered in the form of compounds per se, or as pharmaceutical compositions comprising a prodrug.

[0219] Pharmaceutical compositions comprising the prodrug(s) may be manufactured by means of conventional mixing, dissolving, granulating, dragee-making levigating, emulsifying, encapsulating, entrapping or lyophilization processes. The compositions may be formulated in conventional manner using one or more physiologically acceptable carriers, diluents, excipients or auxiliaries which facilitate processing of the prodrugs into preparations which can be used pharmaceutically.

[0220] The prodrug may be formulated in the pharmaceutical composition per se, or in the form of a hydrate, solvate, N-oxide or pharmaceutically acceptable salt, as previously described. Typically, such salts are more soluble in aqueous solutions than the corresponding free acids and bases, but salts having lower solubility than the corresponding free acids and bases may also be formed.

[0221] Pharmaceutical compositions may take a form suitable for virtually any mode of administration, including, for example, topical, ocular, oral, buccal, systemic, nasal, injection, transdermal, rectal, vaginal, etc., or a form suitable for administration by inhalation or insufflation.

[0222] For topical administration, the prodrug(s) may be formulated as solutions, gels, ointments, creams, suspensions, etc. as are well-known in the art.

[0223] Systemic formulations include those designed for administration by injection, e.g., subcutaneous, intravenous, intramuscular, intrathecal or intraperitoneal injection, as well as those designed for transdermal, transmucosal oral or pulmonary administration.

[0224] Useful injectable preparations include sterile suspensions, solutions or emulsions of the active compound(s) in aqueous or oily vehicles. The compositions may also contain formulating agents, such as suspending, stabilizing and/or dispersing agent. The formulations for injection may be presented in unit dosage form, e.g., in ampules or in multidose containers, and may contain added preservatives.

[0225] Alternatively, the injectable formulation may be provided in powder form for reconstitution with a suitable vehicle, including but not limited to sterile pyrogen free water, buffer, dextrose solution, etc., before use. To this end, the active compound(s) may be dried by any art-known technique, such as lyophilization, and reconstituted prior to use.

[0226] For transmucosal administration, penetrants appropriate to the barrier to be permeated are used in the formulation. Such penetrants are known in the art.

[0227] For oral administration, the pharmaceutical compositions may take the form of, for example, lozenges, tablets or capsules prepared by conventional means with pharmaceutically acceptable excipients such as binding agents (e.g., pregelatinised maize starch, polyvinylpyrrolidone or hydroxypropyl methylcellulose); fillers (e.g., lactose, microcrystalline cellulose or calcium hydrogen phosphate); lubricants (e.g., magnesium stearate, talc or silica); disintegrants (e.g., potato starch or sodium starch glycolate); or wetting agents (e.g., sodium lauryl sulfate). The tablets may be coated by methods well known in the art with, for example, sugars, films or enteric coatings. Phosphate prodrugs in which the progroup(s) is of the formula (CR.sup.dR.sup.d).sub.yOP(O)(OH).sub.2, where each R.sup.d is, independently of the others, selected from hydrogen and lower alkyl and y is 1 or 2 and that exhibit a water-solubility in the range of about 0.1 to 1000 mg/ml at physiological pH are especially suited for oral administration via tablets and capsules. When administered t Sprague-Dawley rats orally from capsules, prodrug Compound 4 exhibits a bioavailability of drug Compound 1 of about 30% (see FIG. 5), with absorption being nearly identical to that of active drug Compound 1 (see FIG. 6). Other phosphate prodrugs having water-solubility properties similar to those of prodrug Compound 4 are expected to exhibit similar pharmacokinetic properties.

[0228] A specific exemplary tablet formulation for prodrug Compound 4 (as well as other phosphate-containing prodrugs) contains about 50-400 mg prodrug compound (or a salt thereof), about 0.05 to 0.5 wt % colloidal silicon dioxide, about 0.5 to 5.0 wt % croscarmellose sodium, about 0.25 to 5.0 wt % magnesium stearate and about 20 to 80 wt % microcrystalline cellulose. If desired, the tablets can be coated with a film, such as a hypromellose film carboxymethyl cellulose or fructose, which can optionally contain coloring agents, such as for example FD&C blue #1, PD&C green #3, FD&C yellow #6 and titanium dioxide.

[0229] Liquid preparations for oral administration may take the form of, for example, elixirs, solutions, syrups or suspensions, or they may be presented as a dry product for constitution with water or other suitable vehicle before use. Such liquid preparations may be prepared by conventional means with pharmaceutically acceptable additives such as suspending agents (e.g., sorbitol syrup, cellulose derivatives or hydrogenated edible fats); emulsifying agents (e.g., lecithin or acacia); non-aqueous vehicles (e.g., almond oil, oily esters, ethyl alcohol, Cremophore or fractionated vegetable oils); and preservatives (e.g., methyl or propyl-p-hydroxybenzoates or sorbic acid). The preparations may also contain buffer salts, preservatives, flavoring, coloring and sweetening agents as appropriate.

[0230] Preparations for oral administration may be suitably formulated to give controlled release of the prodrug, as is well known.

[0231] For buccal administration, the compositions may take the form of tablets or lozenges formulated in conventional manner.

[0232] For rectal and vaginal routes of administration, the prodrug(s) may be formulated as solutions (for retention enemas) suppositories or ointments containing conventional suppository bases such as cocoa butter or other glycerides.

[0233] For nasal administration or administration by inhalation or insufflation, the prodrug(s) can be conveniently delivered in the form of an aerosol spray from pressurized packs or a nebulizer with the use of a suitable propellant, e.g., dichlorodifluoromethane, trichlorofluoromethane, dichlorotetrafluoroethane, fluorocarbons, carbon dioxide or other suitable gas. In the case of a pressurized aerosol, the dosage unit may be determined by providing a valve to deliver a metered amount. Capsules and cartridges for use in an inhaler or insufflator (for example capsules and cartridges comprised of gelatin) may be formulated containing a powder mix of the compound and a suitable powder base such as lactose or starch.

[0234] For ocular administration, the prodrug(s) may be formulated as a solution, emulsion, suspension, etc. suitable for administration to the eye. A variety of vehicles suitable for administering compounds to the eye are known in the art. Specific non-limiting examples are described in U.S. Pat. Nos. 6,261,547; 6,197,934; 6,056,950; 5,800,807; 5,776,445; 5,698,219; 5,521,222; 5,403,841; 5,077,033; 4,882,150; and 4,738,851.

[0235] For prolonged delivery, the prodrug(s) can be formulated as a depot preparation for administration by implantation or intramuscular injection. The prodrug(s) may be formulated with suitable polymeric or hydrophobic materials (e.g., as an emulsion in an acceptable oil) or ion exchange resins, or as sparingly soluble derivatives, e.g., as a sparingly soluble salt. Alternatively, transdermal delivery systems manufactured as an adhesive disc or patch which slowly releases the prodrug(s) for percutaneous absorption may be used. To this end, permeation enhancers may be used to facilitate transdermal penetration of the prodrug(s). Suitable transdermal patches are described in for example, U.S. Pat. No. 5,407,713.; U.S. Pat. Nos. 5,352,456; 5,332,213; 5,336,168; 5,290,561; 5,254,346; 5,164,189; 5,163,899; 5,088,977; 5,087,240; 5,008,110; and 4,921,475.

[0236] Alternatively, other pharmaceutical delivery systems may be employed. Liposomes and emulsions are well-known examples of delivery vehicles that may be used to deliver prodrug(s). Certain organic solvents such as dimethylsulfoxide (DMSO) may also be employed, although usually at the cost of greater toxicity.

[0237] The pharmaceutical compositions may, if desired, be presented in a pack or dispenser device which may contain one or more unit dosage forms containing the prodrug(s). The pack may, for example, comprise metal or plastic foil, such as a blister pack. The pack or dispenser device may be accompanied by instructions for administration.

6.6 Effective Dosages

[0238] The prodrug(s) described herein, or compositions thereof, will generally be used in an amount effective to achieve the intended result, for example in an amount effective to treat or prevent the particular disease being treated. The prodrug(s) may be administered therapeutically to achieve therapeutic benefit or prophylactically to achieve prophylactic benefit. By therapeutic benefit is meant eradication or amelioration of the underlying disorder being treated and/or eradication or amelioration of one or more of the symptoms associated with the underlying disorder such that the patient reports an improvement in feeling or condition, notwithstanding that the patient may still be afflicted with the underlying disorder. For example, administration of a compound to a patient suffering from an allergy provides therapeutic benefit not only when the underlying allergic response is eradicated or ameliorated, but also when the patient reports a decrease in the severity or duration of the symptoms associated with the allergy following exposure to the allergen. As another example, therapeutic benefit in the context of asthma includes an improvement in respiration following the onset of an asthmatic attack, or a reduction in the frequency or severity of asthmatic episodes. Therapeutic benefit in the context of RA also includes the ACR20, or ACR50 or ACR70, as previously described. Therapeutic benefit also generally includes halting or slowing the progression of the disease, regardless of whether improvement is realized.

[0239] For prophylactic administration, the prodrug(s) may be administered to a patient at risk of developing one of the previously described diseases. For example, if it is unknown whether a patient is allergic to a particular drug, the prodrug(s) may be administered prior to administration of the drug to avoid or ameliorate an allergic response to the drug. Alternatively, prophylactic administration may be applied to avoid the onset of symptoms in a patient diagnosed with the underlying disorder. For example, the prodrug(s) may be administered to an allergy sufferer prior to expected exposure to the allergen. Prodrug(s) may also be administered prophylactically to healthy individuals who are repeatedly exposed to agents known to one of the above-described maladies to prevent the onset of the disorder. For example, prodrug(s) may be administered to a healthy individual who is repeatedly exposed to an allergen known to induce allergies, such as latex, in an effort to prevent the individual from developing an allergy. Alternatively, prodrug(s) may be administered to a patient suffering from asthma prior to partaking in activities which trigger asthma attacks to lessen the severity of, or avoid altogether, an asthmatic episode.

[0240] The amount of prodrug(s) administered will depend upon a variety of factors, including, for example, the particular indication being treated, the mode of administration, whether the desired benefit is prophylactic or therapeutic, the severity of the indication being treated and the age and weight of the patient, the bioavailability of the particular prodrug(s) the conversation rate and efficiency into active drug compound under the selected route of administration, etc. Determination of an effective dosage of prodrug(s) for a particular use and mode of administration is well within the capabilities of those skilled in the art.

[0241] Effective dosages may be estimated initially from in vitro activity and metabolism assays. For example, an initial dosage of prodrug for use in animals may be formulated to achieve a circulating blood or serum concentration of the metabolite active compound that is at or above an IC.sub.50 of the particular compound as measured in as in vitro assay, such as the in vitro CHMC or BMMC and other in vitro assays described in U.S. application Ser. No. 10/355,543 filed Jan. 31, 2003 (US2004/0029902A1), international application Serial No. PCT/US03/03022 filed Jan. 31, 2003 (WO 03/063794), U.S. application Ser. No. 10/631,029 filed Jul. 29, 2003 (______), international application Serial No. PCT/US03/24087 (WO2004/014382), U.S. application Ser. No. 10/903,263 filed Jul. 30, 2004 (US2005/0234049), and international application Serial No. PCT/US2004/24716 (______). Calculating dosages to achieve such circulating blood or serum concentrations taking into account the bioavailability of the particular prodrug via the desired route of administration is well within the capabilities of skilled artisans. For guidance, the reader is referred to Fingl & Woodbury, General Principles, In: Goodman and Gilman's The Pharmaceutical Basis of Therapeutics, Chapter 1, pp. 1-46, latest edition, Pagamonon Press, and the references cited therein.

[0242] Initial dosages of prodrug can also be estimated from in vivo data, such as animal models. Animal models useful for testing the efficacy of the active metabolites to treat or prevent the various diseases described above are well-known in the art. Suitable animal models of hypersensitivity or allergic reactions are described in Foster, 1995, Allergy 50(21Suppl):6-9, discussion 34-38 and Tumas et al., 2001, J. Allergy Clin. Immunol. 107(6):1025-1033. Suitable animal models of allergic rhinitis are described in Szelenyi et al., 2000, Arzneimittelforschung 50(11):1037-42; Kawaguchi et al., 1994, Clin. Exp. Allergy 24(3):238-244 and Sugimoto et al., 2000, Immunopharmacology 48(1):1-7. Suitable animal models of allergic conjunctivitis are described in Carreras et al., 1993, Br. J. Ophthalmol. 77(8):509-514; Saiga et al., 1992, Ophthalmic Res. 24(1):45-50; and Kunert et al., 2001, Invest. Ophthalmol. Vis. Sci. 42(11):2483-2489. Suitable animal models of systemic mastocytosis are described in O'Keefe et al., 1987, J. Vet. Intern. Med. 1(2):75-80 and Bean-Knudsen et al., 1989, Vet. Pathol. 26(1):90-92. Suitable animal models of hyper IgE syndrome are described in Claman et al., 1990, Clin. Immunol. Immunopathol. 56(1):46-53. Suitable animal models of B-cell lymphoma are described in Hough et al., 1998, Proc. Natl. Acad. Sci. USA 95:13853-13858 and Hakim et al., 1996, J. Immunol. 157(12):5503-5511. Suitable animal models of atopic disorders such as atopic dermatitis, atopic eczema and atopic asthma are described in Chan et al., 2001, J. Invest. Dermatol. 117(4):977-983 and Suto et al., 1999, Int. Arch. Allergy Immunol. 120(Suppl 1):70-75. Animal models suitable for testing the bioavailability and/or metabolism of prodrugs into active metabolites are also well-known. Ordinarily skilled artisans can routinely adapt such information to determine dosages of particular prodrugs suitable for human administration. Additional suitable animal models are described in the Examples section.

[0243] Dosage amounts will typically be in the range of from about 0.0001 mg/kg/day, 0.001 mg/kg/day or 0.01 mg/kg/day to about 100 mg/kg/day, but may be higher or lower, depending upon, among other factors, the activity of the active metabolite compound, the bioavailability of the prodrug, its metabolism kinetics and other pharmacokinetic properties, the mode of administration and various other factors, discussed above. Dosage amount and interval may be adjusted individually to provide plasma levels of the prodrug(s) and/or active metabolite compound(s) which are sufficient to maintain therapeutic or prophylactic effect. For example, the prodrugs may be administered once per week, several times per week (e.g., every other day), once per day or multiple times per day, depending upon, among other things, the mode of administration, the specific indication being treated and the judgment of the prescribing physician. In cases of local administration or selective uptake, such as local topical administration, the effective local concentration of prodrug(s) and/or active metabolite compound(s) may not be related to plasma concentration. Skilled artisans will be able to optimize effective local dosages without undue experimentation.

[0244] Preferably, the prodrugs will metabolize into active compound(s) that will provide therapeutic or prophylactic benefit without causing substantial toxicity. Toxicity of the active and other metabolites, as well as the unmetabolized prodrug may be determined using standard pharmaceutical procedures. The dose ratio between toxic and therapeutic (or prophylactic) effect is the therapeutic index. Prodrug(s) that exhibit high therapeutic indices are preferred.

[0245] The inventions having been described, the following examples are offered by way of illustration and not limitation.

7. EXAMPLES

7.1 Synthesis of Prodrug Compound 4

7.1.1 N4-(2,2-dimethyl-4-[(di-tert-butyl phosphonoxy)methyl]-3-oxo-5-pyrido[1,4]oxazin-6-yl)-5-fluoro-N2-(3,4,5-trimethoxyphenyl)-2,4-pyrimidinediamine (Compound 3)

[0246] ##STR00026##

[0247] N4-(2,2-dimethyl-3-oxo-4H-5-pyrido[1,4]oxazin-6-yl)-5-fluoro-N2-(3,4,5-trimethoxyphenyl)-2,4-pyrimidinediamine (1, 1.0 g, 2.12 mmol), Cs.sub.2CO.sub.3 (1.0 g, 3.07 mmol) and di-tert-butyl chloromethyl phosphate (2, 0.67 g, 2.59 mmol) in acetone (20 mL) was stirred at room temperature under nitrogen atmosphere. Progress of the reaction was monitored by LC/MS. Crude reaction mixture displayed three product peaks with close retention times with M.sup.++H 693 (minor-1), 693 (major; 3) and 477 (minor-2) besides starting material (Compound 1). Upon stirring the contents for 4 days (70% consumption), the reaction mixture was concentrated and diluted with water. The resultant pale yellow precipitate formed was collected by filtration and dried. The crude solid was purified by silica gel (pretreated with 10% NEt.sub.3/CH.sub.2Cl.sub.2 followed by eluting with hexanes) column chromatography by gradient elution with 70% EtOAc/hexanes-100% EtOAc). The fractions containing Compound 1 and M.sup.++H 693 were collected and concentrated. The resulting crude white solid was subjected to repurification in the similar manner as described previously but by eluting with 30%-50%-75%-100% EtOAc/hexanes. The major product peak with M.sup.++H 693 was collected as a white solid (270 mg, 18%) and was characterized as N4-(2,2-dimethyl-4-[(di-tert-butyl phosphonoxy)methyl]-3-oxo-5-pyrido[1,4]oxazin-6-yl)-5-fluoro-N2-(3,4,5-trimethoxyphenyl)-2,4-pyrimidinediamine (Compound 3). .sup.1H NMR (DMSO-d6): 9.21 (s, 1H), 9.17 (s, 1H), 8.16 (d, 1H, J=2.6 Hz), 7.76 (d, 1H, J=8.5 Hz), 7.44 (d, 1H, J=8.5 Hz), 7.02 (s, 2H), 5.78 (d, 1H, J.sup.3 pH=6.1 Hz), 3.64 (s, 6H), 3.58 (s, 3H), 1.45 (s, 6H), 1.33 (s, 9H). LCMS: ret. time: 14.70 min.; purity: 95%; MS (m/e): 693 (MH.sup.+). .sup.31P NMR (DMSO-d6): 11.36.

7.1.2 N4-(2,2-dimethyl-4-[(dihydrogen phosphonoxy)methyl]-3-oxo-5-pyrido[1,4]oxazin-6-yl)-5-fluoro-N2-(3,4,5-trimethoxyphenyl)-2,4-pyrimidinediamine (Compound 4)

[0248] Trifluoroacetic acid (1.5 mL) was added dropwise as a neat for 5 min to N4-(2,2-dimethyl-4-[(di-tert-butyl phosphonoxy)methyl]-3-oxo-5-pyrido[1,4]oxazin-6-yl)-5-fluoro-N2-(3,4,5-trimethoxyphenyl)-2,4-pyrimidinediamine (Compound 3, 120 mg, 0.173 mmol) dissolved in CH.sub.2Cl.sub.2 (10 mL) at 0 C. under nitrogen atmosphere. The contents were allowed to stir for 1.5 h. Progress of the reaction mixture was monitored by LC/MS. After complete consumption of the starting material, reaction mixture was concentrated, dried and triturated with ether. The ethereal layer was decanted and dried to provide the crude solid. LC/MS analysis of the crude displayed three peaks with M.sup.++H 581, 471 and 501. The peak corresponding to M.sup.++H 581 was collected by preparative HPLC chromatographic purification. The fractions were lyophilised and dried to provide 53 mg (52%) of off white fluffy solid and characterized as N4-(2,2-dimethyl-4-[(dihydrogen phosphonoxy)methyl]-3-oxo-5-pyrido[1,4]oxazin-6-yl)-5-fluoro-N2-(3,4,5-trimethoxyphenyl)-2,4-pyrimidinediamine (Compound 4). .sup.1H NMR (DMSO-d6): 9.21 (br s, 2H), 8.16 (d, 1H, J=2.6 Hz), 7.93 (d, 1H, J=8.5 Hz), 7.39 (d, 1H, J=8.5 Hz), 7.05 (s, 2H), 5.79 (d, 1H, J.sup.3 pH=6.6 Hz), 3.67 (s, 6H), 3.59 (s, 3H), 1.44 (s, 6H). LCMS: ret. time: 8.52 min.; purity: 95%; MS (m/e): 581 (MH.sup.+). .sup.31P NMR (DMSO-d6): 2.17.

7.2 Alternative Synthesis of Prodrug Compound 4

[0249] An alternative method of synthesizing prodrug Compound 4 which alleviates the need for column chromatography and HPLC purification is provided below.

7.2.1 Synthesis of N4-(2,2-dimethyl-4-[(di-tert-butyl phosphonoxy)methyl]-3-oxo-5-pyrido[1,4]oxazin-6-yl)-5-fluoro-N2-(3,4,5-trimethoxyphenyl)-2,4-pyrimidinediamine (Compound 3)

[0250] ##STR00027##

[0251] N4-(2,2-dimethyl-3-oxo-4H-5-pyrido[1,4]oxazin-6-yl)-5-fluoro-N2-(3,4,5-trimethoxyphenyl)-2,4-pyrimidinediamine (Compound 1, 19.73 g, 41.97 mmol), Cs.sub.2CO.sub.3 (15.04 g, 46.16 mmol) and di-tert-butyl chloromethyl phosphate (13.0 g, 50.38 mmol) in DMF (100 mL) was stirred at room temperature under nitrogen atmosphere. Progress of the reaction was monitored by in process LC/MS. Crude reaction mixture displayed two product peaks (ratio 1:6.5) with close retention times displaying M.sup.++H 693 (minor) and 693 (major) besides starting material (Compound 1). Initial yellow reaction mixture turned to olive green as the reaction progressed. Workup is carried out as follows

[0252] 1). Upon stirring the contents for 30 h (92% consumption), reaction mixture was poured onto ice-water (400 mL) and stirred the contents by adding brine solution (200 mL). Fine yellow tan solid formed was filtered, washed with water and dried overnight.

[0253] 2). The solid (35 g) was dissolved in MTBE (500 mL) and washed with water (400 mL). Aqueous layer was extracted with MTBE (2350 mL) till the absence of UV on TLC. Combined organic layers were dried over anhydrous Na.sub.2SO.sub.4 and decanted. Note: step 2 can be done directly, however, DMF extraction back into solution leads to difficulty in the crystallization step.

[0254] 3). The dark red clear solution was subjected to 10 g of activated charcoal treatment, heated to boil and filtered.

[0255] 4). The dark red clear solution was concentrated by normal heating to 400 mL of its volume and left for crystallization. The solid crystallized as granules was filtered, crushed the granules to powder, washed with MTBE (400 mL) and dried under high vacuum. See step 7 for the workup of mother liquor. Weight of the solid: 17 g; purity: 90% (Compound 3), 6.26% (Compound 1), 1.8% (minor M.sup.+693).

[0256] 5). At this stage solid was taken in 500 ml of ethylether and heated to boil. Cooled and filtered to remove undissolved material. Filtrate was concentrated.

[0257] 6). Above concentrate was subjected to crystallization in MTBE (300 mL). The white solid formed was filtered, washed with MTBE (100 mL) and dried under high vacuum to provide the desired N4-(2,2-dimethyl-4-[(di-tert-butyl phosphonoxy)methyl]-3-oxo-5-pyrido[1,4]oxazin-6-yl)-5-fluoro-N2-(3,4,5-trimethoxyphenyl)-2,4-pyrimidinediamine (Compound 3) in 97% purity. .sup.1H NMR (DMSO-d6): 9.21 (s, 1H), 9.17 (s, 1H), 8.16 (d, 1H, J=2.6 Hz), 7.76 (d, 1H, J=8.5 Hz), 7.44 (d, 1H, J=8.5 Hz), 7.02 (s, 2H), 5.78 (d, 1H, J.sup.3.sub.PH=6.1 Hz), 3.64 (s, 6H), 3.58 (s, 3H), 1.45 (s, 6H), 1.33 (s, 9H). LCMS: ret. time: 14.70 min.; purity: 95%; MS (m/e): 693 (MH.sup.+). .sup.31P NMR (DMSO-d6): 11.36. Weight of the solid: 15.64 g (yield: 55%); purity: 97% (R935787), 3% (Compound 1).

[0258] 7). Mother liquor was concentrated and steps 5 and 6 were repeated to provide Compound 3.

7.2.2 Synthesis of N4-(2,2-dimethyl-4-[(dihydrogen phosphonoxy)methyl]-3-oxo-5-pyrido[1,4]oxazin-6-yl)-5-fluoro-N2-(3,4,5-trimethoxyphenyl)-2,4-pyrimidinediamine (Compound 4)

[0259] N4-(2,2-dimethyl-4-[(di-tert-butyl phosphonoxy)methyl]-3-oxo-5-pyrido[1,4]oxazin-6-yl)-5-fluoro-N2-(3,4,5-trimethoxyphenyl)-2,4-pyrimidinediamine (Compound 3); (15.0 g, 21.67 mmol) dissolved in AcOH:H.sub.2O (225 mL, 4:1) was heated at 65 C. (oil bath temp). The progress of the reaction was monitored by in process LC/MS. The reaction mixture transformed to faint tan white solid after 1 h of heating. At this point most of Compound 3 converted to mono des t-butyl product. After 3 h of heating, consumption of SM and complete conversion of intermediate (mono des t-butylated) to product was observed.

[0260] Reaction mixture was cooled, poured onto ice-water (200 mL), stirred for 20 min and filtered. The clear white filter cake was washed with water (600 ml) and acetone (200 mL) successively, dried for 2 h followed by drying under high vacuum over P.sub.2O.sub.5 in a desiccator. Weight of the solid: 12.70 g; purity: 97% (Compound 3) and 3% (Compound 1).sup.1H NMR indicated acetic acid presence (1:1)

[0261] To remove acetic acid, the solid was taken in acetonitrile (300 mL) and concentrated by rotovap vacuum. This process was repeated 2 times with acetonitrile and toluene (3300 mL). The solid obtained was dried under high vacuum at 50 C.

[0262] Finally, the solid was taken in acetone (400 mL), filtered and dried to provide N4-(2,2-dimethyl-4-[(dihydrogen phosphonoxy)methyl]-3-oxo-5-pyrido[1,4]oxazin-6-yl)-5-fluoro-N2-(3,4,5-trimethoxyphenyl)-2,4-pyrimidinediamine (Compound 4). .sup.1H NMR (DMSO-d6): 9.21 (br s, 2H), 8.16 (d, 1H, J=2.6 Hz), 7.93 (d, 1H, J=8.5 Hz), 7.39 (d, 1H, J=8.5 Hz), 7.05 (s, 2H), 5.79 (d, 1H, J.sup.3.sub.PH=6.6 Hz), 3.67 (s, 6H), 3.59 (s, 3H), 1.44 (s, 6H). LCMS: ret. time: 8.52 min.; purity: 95%; MS (m/e): 581 (MH.sup.+). .sup.31P NMR (DMSO-d6): 2.17.

7.3 Synthesis of N4-(2,2-dimethyl-4-[(dihydrogen phosphonoxy)methyl]-3-oxo-5-pyrido[1,4]oxazin-6-yl)-5-fluoro-N2-(3,4,5-trimethoxyphenyl)-2,4-pyrimidinediamine Mono Calcium Salt (Compound 6)

[0263] ##STR00028##

[0264] Aqueous (10 mL) NaHCO.sub.3 (0.17 g, 2.02 mmol) solution was added dropwise to a suspension of N4-(2,2-dimethyl-4-[(dihydrogen phosphonoxy)methyl]-3-oxo-5-pyrido[1,4]oxazin-6-yl)-5-fluoro-N2-(3,4,5-trimethoxyphenyl)-2,4-pyrimidinediamine (0.5 g, 0.86 mmol) in water (5 mL) at room temperature while stirring the contents. The clear solution formed was treated with aqueous (10 mL) CaCl.sub.2 (0.11 g in 10 mL water, 0.99 mmol) in a dropwise manner at room temperature. The addition resulted in the precipitation of a white solid from reaction mixture. Upon completion of addition, the contents were stirred for a period of 30 min, filtered, washed with water (40 mL) and dried. The clear white solid was taken in water (30 mL) and heated on a stir plate to boil. The solution was cooled, filtered and dried. The white solid collected and further dried under high vacuo at 80 C. for 32 h to provide 0.41 g (83%) of N4-(2,2-dimethyl-4-[(dihydrogen phosphonoxy)methyl]-3-oxo-5-pyrido[1,4]oxazin-6-yl)-5-fluoro-N2-(3,4,5-trimethoxyphenyl)-2,4-pyrimidinediamine mono calcium salt (Compound 6).

7.4 Synthesis of Prodrug Compound 8

[0265] ##STR00029##

[0266] N4-(2,2-dimethyl-4-[(di-tert-butyl phosphonoxy)methyl]-3-oxo-5-pyrido[1,4]oxazin-6-yl)-5-fluoro-N2-(3,4,5-trimethoxyphenyl)-2,4-pyrimidinediamine (prepared as described above) (0.2 g, 0.29 mmol) was added to a mixture of MeOH(5 mL) and Et.sub.2O (5 mL). 2N aq. NaOH (0.023 g, 0.58 mmol) was added at once while stirring the contents at room temperature. Progress of the reaction was monitored by LC/MS. After 8 h of stirring, the solid precipitated was filtered and dried to provide N4-(2,2-dimethyl-4-methoxymethyl-3-oxo-5-pyrido[1,4]oxazin-6-yl)-5-fluoro-N2-(3,4,5-trimethoxyphenyl)-2,4-pyrimidinediamine (Compound 8) as a white solid (0.11 g, 74%). .sup.1H NMR (DMSO-d6): 9.47 (s, 1H), 9.15 (s, 1H), 8.16 (d, 1H, J=3.8 Hz), 7.87 (d, 1H, J=8.5 Hz), 7.37 (d, 1H, J=8.5 Hz), 7.03 (s, 2H), 5.40 (s, 2H), 3.66 (s, 6H), 3.59 (s, 3H), 3.27 (s, 3H), 1.44 (s, 6H). LCMS: ret. time: 12.88 min.; purity: 92%; MS (m/e): 515 (MH.sup.+).

7.5 The Active 2,4-Pyrimidinediamine Compounds Are Tolerated In Animals

[0267] The ability of numerous biologically active 2,4-pyrimidinediamine compounds to exert their activity at doses below those exhibiting toxicity in animals has been demonstrated previously (see, e.g., U.S. application Ser. No. 10/355,543 filed Jan. 31, 2003 (US2004/0029902A1), international application Serial No. PCT/US03/03022 filed Jan. 31, 2003 (WO 03/063794), U.S. application Ser. No. 10/631,029 filed Jul. 29, 2003 (______), international application Serial No. PCT/US03/24087 (WO2004/014382), U.S. application Ser. No. 10/903,263 filed Jul. 30, 2004 (US2005/0234049), and international application Serial No. PCT/US2004/24716 (______).

[0268] The safety pharmacology of active Compound 1 has been studied in a core battery of studies (respiratory, CNS, cardiovascular, and HERG). A slight reduction in heart rate and increase in RR interval was noted at 50 mg/kg in the cardiovascular study and a slight effect on a few behavioral parameters at 50 mg/kg was also noted in the CNS (Irwin) study. Otherwise the safety pharmacology studies determined that Compound 1 was well tolerated. GLP toxicology studies included negative mutagenicity and clastogenicity studies (Ames, chromosomal aberration, and mouse micronucleus). In 28-day toxicity studies in rats and monkeys, higher doses had evidence of a reversible effect on hematology, liver transaminase (mild effect in the rat only), spleen and thymus size (rat only) and bone marrow cellularity (rat and monkey). Immunophenotyping in the rat study revealed a significant decrease in the percentage of CD3+ cells in high dose rats while a significant increase in CD45RA+ cells was noted following recovery. Histopathology was noteworthy only for mild reductions in marrow cellularity at high doses. There was no evidence for untoward effects on humoral immunity in the anti-KLH antibody assessment. The No Observed Adverse Effect Level (NOAEL) is 10-30 mg/kg/day for rats and 100 mg/kg/day for monkeys.

7.6 Drug Compound 1 is Biologically Active in In Vitro Assays

[0269] Compound 1 blocks FcRI-dependent activation of Cord-Blood Derived Primary Human Mast Cells (CHMC) in a dose-dependent manner with an EC.sub.50 of approximately 43 nM as assessed by measuring the activity of tryptase released upon degranulation. Compound 1 does not inhibit ionomycin-induced degranulation of CHMCs. Ionomycin is a calcium ionophore that induces CHMC degranulation bypassing early FcR signaling, thus indicating that Compound 1 is specific to FcR signaling, and not degranulation per se. Compound 1 also inhibits the FcRI-dependent production and release of LTC4 (EC.sub.50=39 nM) and all cytokines tested (EC.sub.50 ranging from 158 nM-462 nM).

7.7 Drug Compound 1 is Effective in Animal Models of Rheumatoid Arthritis

[0270] The biologic activity of Compound 1 in IC-mediated vascular edema (Arthus reaction in the rat), in collagen antibody-induced arthritis in the mouse, and in a rat model of collagen-induced arthritis.

7.7.1 Arthus Reaction

[0271] IC-mediated acute inflammatory tissue injury is implicated in a variety of human autoimmune diseases, including vasculitis, serum sickness, systemic lupus erythematosus, RA, and glomerulonephritis. The classical experimental model for IC-mediated tissue injury is the Reverse Passive Arthus (RPA) reaction. Intravenous injection of antigen (ovalbumin, OVA) following intradermal injection of antibodies specific to OVA (rabbit anti-OVA IgG) results in perivascular deposition of IC and a rapid inflammatory response characterized by edema, neutrophil infiltration, and hemorrhage at the injection sites (Szalai, et al., 2000, J. Immunol. 164(1):463-468).

[0272] A single oral treatment of rats with Compound 1 one hour prior to antigen/antibody administration reduced the cutaneous RPA reaction and inflammatory edema in a dose-dependent manner. Administration of 10 mg/kg oral Compound 1 inhibited extravascular leakage of Evans blue dye (OD.sub.610) from tissue biopsies by 80% compared with vehicle control.

7.7.2 Collagen Antibody-Induced Arthritis

[0273] The anti-inflammatory activity of Compound 1 was evaluated in the mouse collagen antibody-induced arthritis (CAIA) model in which an anti-type II collagen antibody cocktail is applied to induce arthritis (Teroto et al., 1992, J. Immunol. 148(7):2103-2108; McCoy et al., 2002, J. Clin. Invest. 110(5):651-658; Kagari et al., 2002, J. Immunol. 169(3):1459-1466). This passive model differs from the traditional rodent collagen-induced arthritis (CIA) in that disease symptoms appear quickly (developing within 24-48 hrs after an IV-injection of antibodies), arthritis is inducible in both CIA-susceptible and CIA-resistant mouse strains, and it allows evaluation of inflammation that is independent of antibody production.

[0274] CAIA was induced in Balb/c mice by intravenous injection of Arthrogen-CIA Monoclonal Antibody Blend (Chemicon International, Inc., Temecula, Calif.) via the tail vein, followed 2 days later by an intraperitoneal injection of LPS. Oral Compound 1 treatment was started within 4 hours of antibody administration (Day 0). The severity of the arthritis in hind-paws was scored daily (scale of 0-4 per paw, sum of scores for both hind paws). By Day 5, both control groups, saline and vehicle, reached their peak clinical score with a disease incidence of 100%.

[0275] Reduced inflammation and swelling was evident in animals treated with Compound 1, and the arthritis progressed more slowly. Treatment with Compound 1 (b.i.d.) significantly reduced clinical arthritis (p<0.05) compared with animals treated with vehicle only, while lower dose levels of Compound 1 showed a trend toward reduced arthritis severity, disease incidence, and time of onset; however, the differences were not significant (p>0.05).

7.7.3 Collagen-Induced Arthritis

[0276] One of the experimental models for IC-mediated tissue injury is the CIA in rodents (Kleinau et al., 2000, J. Exp. Med. 191:1611-1616). Injection of type II collagen (CII) into rodents produces an immune reaction that characteristically involves inflammatory destruction of cartilage and bone of the distal joints with concomitant swelling of surrounding tissues. CIA in rats is commonly used to evaluate compounds that might be of potential use as drugs for treatment of rheumatoid arthritis and other chronic inflammatory conditions and is induced in susceptible strains of either mice or rats by injection of CII in incomplete Freund's adjuvant (IFA). Administration of this emulsion gives rise to polyarthritis, characterized by synovial hyperplasia, infiltration of mononuclear cells, pannus formation, and destruction of cartilage and bone. It has been previously well documented that antibodies to CII are a prerequisite for CIA in mice, as B-cell deficient mice do not develop arthritis (Svensson et al., 1998, Clin. Exp. Immunol. 111:521-526).

[0277] Syngeneic LOU rats were immunized on Day 0 with native chicken CII/IFA. Oral treatment began at the onset of arthritis symptoms (Day 10). A total of 59 rats were treated with either a vehicle control or Compound 1 at one of four dose levels (1, 3, 10, and 30 mg/kg, q.d. by p.o. gavage). Hind limbs were scored daily for clinical arthritis severity using a standardized method based on the degree of joint inflammation. High resolution digital radiographs of hind limbs were obtained at the conclusion of the study (Day 28). These limbs were also analyzed for histopathologic changes. IgG antibodies to native CII were measured in quadruplicate by ELISA. There was a significant reduction (p<0.05) in arthritis severity that was evident within 7 days after initiation of therapy in the high-dose (30 mg/kg) group that continued to improve throughout the study. By Day 28, the clinical score in the animals treated with vehicle alone was 6.080.67 compared to 2.540.98 in the Compound 1 30 mg/kg group (p<0.001). Blinded radiographs at study termination (Day 28), demonstrated a significant reduction in joint damage: 3.660.71 (vehicle) vs. 1.630.67 (Compound 1) (p<0.02) (E. Brahn. 2004). Blinded composite histopathologic studies confirmed the regression of pannus and erosions: Mean modified Mankin scores were 11.80.9 (vehicle) vs. 3.70.9 (30 mg/kg Compound 1) (p<0.001). Antibodies to native CII were not decreased in Compound 1-treated rats.

7.8 The Prodrug Compounds Are Orally Bioavailable

[0278] Prodrug Compound 4 was tested for oral bioavailability. For the study, the prodrug was dissolved in various vehicles (e.g. PEG 400 solution and CMC suspension) for intravenous and oral dosing in the rats. Where indicated, the active metabolite Compound 1 compound (drug) was formulated and administered in the same vehicles. Following administration of the prodrug and/or drug, plasma samples were obtained and extracted. The plasma concentrations of the prodrug and/or drug were determined by high performance liquid chromatography/tandem mass spectrometry (LC/MS/MS) methods. Pharmacokinetic analyses were performed based on the plasma concentration data. The pharmacokinetic parameters of interest include Clearance (CL), Volume of distribution at steady-state (Vss), terminal half-life (t.sub.1/2), and oral bioavailability (% F).

[0279] The results of these various pharmacokinetic experiments are illustrated in FIGS. 4-12.

[0280] Referring to FIG. 4, PK profiles are shown for IV and PO administration in Spraque-Dawley rats. For IV administration, Compound 4 was dissolved in PEG-400 and administered at a dose of 1 mg/kg. Rapid disappearance of prodrug Compound 4 was observed and drug Compound 1 was found in plasma samples obtained from the jugular vein. Given orally in the same vehicle, no prodrug Compound 4 was present systemically, but high levels of drug metabolite Compound 1 were observed.

[0281] FIG. 5 summarizes the PK parameters for the study described in FIG. 4. Prodrug Compound 4 is rapidly cleared and, in part, converted to drug Compound 1. Given orally at a dose of 4 mg/kg, bioavailability was determined to be 29.9%. This bioavailability number is based on data obtained from a previous study (data not shown) in which drug Compound 1 was administered as an IV bolus dose at 1 mg/kg.

[0282] FIG. 6 compares drug Compound 1 exposure in Sprague-Dawley rats following oral administration of either drug Compound 1 (2.5 mg/kg in PEG-400) or prodrug Compound 4 (4 mg/kg in PEG-400). The values for AUC/dose are nearly identical indicating that the prodrug Compound 4 is absorbed equally as well as drug Compound 1.

[0283] FIG. 7 shows a plot of cLogD vs pH calculated using in-situ predictions for both Compound 1 and Compound 4. Compound 1 is highly lipophilic and only weakly ionizable (measured solubility is less than 1 mcg/ml in phosphate buffer at pH=7.5, data not shown). In contrast, Compound 4 is highly polar at neutral pH. Measured solubility values are consistent with the predicted cLogD values at pH=7.5.

[0284] FIG. 8 demonstrates that prodrug Compound 4 is stable under acidic and neutral conditions at 37 C.

[0285] FIG. 9 illustrates the conversion of prodrug Compound 4 to drug Compound 1 in microsome preparations. Prodrug Compound 4 failed to convert to drug Compound 1 in microsomal preparations obtained from Xenotech. In follow-up studies using intestinal and hepatic microsomes obtained from a different source, conversion of Compound 4 to Compound 1 was observed (data not shown).

[0286] FIG. 10 illustrates that prodrug Compound 4 is unstable in rat plasmahydrolysis to drug Compound 1 is observed and the conversion to Compound 1 is thought to be catalyzed by phosphatase enzymes. The presence of Phosphatase activity in rat plasma was confirmed using p-nitrophenyl phosphatea known substrate for phosphatase.

[0287] FIG. 11 illustrates the absorption of prodrug Compound 4 from different vehicles. Unlike drug Compound 1, absorption of prodrug Compound 4 is not dependent on formulation. Prodrug Compound 4 is absorbed equally well in solution formulations (PEG-400 and carboxymethylcellulose (CMC)) and as a powder in hard gelatin capsules.

[0288] Based on the pharmacokinetic data, the oral bioavailability (% F) of prodrug Compound 4 from all three vehicles tested (PEG-400 solution; CMC Solution; and powder in capsules) was determined to be approx. 30%.