Processes for the convergent synthesis of calicheamicin derivatives

Abstract

This invention describes processes for the convergent synthesis of calicheamicin derivatives, and similar analogs using bifunctional and trifunctional linker intermediates.

Claims

1. A trifunctional linker intermediate, of the formula ##STR00069## wherein: Alk.sup.1 is a branched or unbranched alkylene chain of 2 to 6 carbon atoms; Sp.sup.1 is selected from —S—, —O—, —CONH—, —NHCO—, and —NR′—; Z.sup.1 is H, or alkyl of 1 to 5 carbon atoms; Ar is 1,2-, 1,3-, or 1,4-phenylene optionally substituted with one, two, or three groups independently selected from alkyl of 1 to 6 carbon atoms, alkoxy of 1 to 5 carbon atoms, thioalkoxy of 1 to 4 carbon atoms, halogen, nitro, —COOR′, —CONHR′, —O(CH.sub.2).sub.nCOOR′, —S(CH.sub.2).sub.nCOOR′, —O(CH.sub.2).sub.nCONHR′, and —S(CH.sub.2).sub.nCONHR′ or a 1,2-, 1,3-, 1,4-, 1,5-, 1,6-, 1,7-, 1,8-, 2,3-, 2,6-, or 2,7-naphthylidene optionally substituted with one, two, three, or four groups independently selected from alkyl of 1 to 6 carbon atoms, alkoxy of 1 to 5 carbon atoms, thioalkoxy of 1 to 4 carbon atoms, halogen, nitro, —COOR′, —CONHR′, —O(CH.sub.2).sub.nCOOR′, —S(CH.sub.2).sub.nCOOR′, —O(CH.sub.2).sub.nCONHR′, and —S(CH.sub.2).sub.nCONHR′; n is an integer from 0 to 5; R′ is a straight or branched alkyl of 1 to 5 carbon atoms optionally substituted by one or two groups of —OH, alkoxy of 1 to 4 carbon atoms, thioalkoxy of 1 to 4 carbon atoms; Sp is a straight or branched-chain divalent or trivalent alkyl radical of 1 to 18 carbon atoms, divalent or trivalent aryl or heteroaryl radical, divalent or trivalent cycloalkyl of 3 to 18 carbon atoms or heterocycloalkyl radical, divalent or trivalent aryl- or heteroaryl-alkyl (C1-C18) radical, divalent or trivalent cycloalkyl- or heterocyclo-alkyl-alkyl (C1-C18) radical or divalent or trivalent unsaturated alkyl radical of 2 to 18 carbon atoms, wherein heteroaryl is furyl, thienyl, N-methylpyrrolyl, pyridinyl, N-methylimidazolyl, oxazolyl, pyrimidinyl, quinolyl, isoquinolyl, N-methylcarbazoyl, aminocoumarinyl, or phenazinyl and wherein if Sp is a trivalent radical, it can be additionally substituted by dialkylamino of 1 to 5 carbon atoms, alkoxy of 1 to 5 carbon atoms, hydroxy, or alkylthio of 1 to 5 carbon atoms groups; Q is selected from the group consisting of —NNHCO—, —NNHCS—, and —NNHCONH—; Z is selected from the group consisting of ##STR00070##

2. The trifunctional linker intermediate of claim 1, wherein Z is N-hydroxysuccinimide.

3. The trifunctional linker intermediate of claim 1, wherein Alk.sup.1 is a branched or unbranched alkylene chain of 2 to 5 carbon atoms.

4. The trifunctional linker intermediate of claim 1, wherein Alk.sup.1 is a branched or unbranched alkylene chain of 3 carbon atoms.

5. The trifunctional linker intermediate of claim 1, wherein Sp.sup.1 is an oxygen atom.

6. The trifunctional linker intermediate of claim 1, wherein Z.sup.1 is alkyl of 1 to 3 carbon atoms.

7. The trifunctional linker intermediate of claim 1, wherein Z.sup.1 is methyl.

8. The trifunctional linker intermediate of claim 1, wherein Ar is selected from the group consisting of 1,2-phenylene, 1,3-phenylene, 1,4-phenylene, 1,2-naphthylidene, 1,3-naphthylidene, 1,4-naphthylidene, 1,5-naphthylidene, 1,6-naphthylidene, 1,7-naphthylidene, 1,8-naphthylidene, 2,3-naphthylidene, 2,6-naphthylidene, and 2,7-aphthylidene.

9. The trifunctional linker intermediate of claim 1, wherein Ar is 1,4-phenylene.

10. The trifunctional linker intermediate of claim 1, wherein Q is —NNHCO—.

11. The trifunctional linker intermediate of claim 1, wherein Sp is a straight or branched-chain divalent or trivalent alkyl radical of 1 to 12 carbon atoms.

12. The trifunctional linker intermediate of claim 1, wherein Sp is a straight or branched-chain divalent or trivalent alkyl radical of 1 to 6 carbon atoms.

13. The trifunctional linker intermediate of claim 1, wherein Sp is a straight or branched-chain divalent or trivalent alkyl radical of 4 carbon atoms.

14. The trifunctional linker intermediate of claim 1, having the formula: ##STR00071##

15. A sodium salt of the trifunctional linker intermediate of claim 1.

16. A bilinker carboxylic acid intermediate of the formula ##STR00072## wherein: Alk.sup.1 is a branched or unbranched alkylene chain of 2 to 6 carbon atoms; Sp.sup.1 is selected from —S—, —O—, —CONH—, —NHCO—, and —NR′—; Z.sup.1 is H, or alkyl of 1 to 5 carbon atoms; Ar is 1,2-, 1,3-, or 1,4-phenylene optionally substituted with one, two, or three groups independently selected from alkyl of 1 to 6 carbon atoms, alkoxy of 1 to 5 carbon atoms, thioalkoxy of 1 to 4 carbon atoms, halogen, nitro, —COOR′, —CONHR′, —O(CH.sub.2).sub.nCOOR′, —S(CH.sub.2).sub.nCOOR′, —O(CH.sub.2).sub.nCONHR′, and —S(CH.sub.2).sub.nCONHR′ or a 1,2-, 1,3-, 1,4-, 1,5-, 1,6-, 1,7-, 1,8-, 2,3-, 2,6-, or 2,7-naphthylidene optionally substituted with one, two, three, or four groups independently selected from alkyl of 1 to 6 carbon atoms, alkoxy of 1 to 5 carbon atoms, thioalkoxy of 1 to 4 carbon atoms, halogen, nitro, —COOR′, —CONHR′, —O(CH.sub.2).sub.nCOOR′, —S(CH.sub.2).sub.nCOOR′, —O(CH.sub.2).sub.nCONHR′, and —S(CH.sub.2).sub.nCONHR′; n is an integer from 0 to 5; R′ is a straight or branched alkyl of 1 to 5 carbon atoms optionally substituted by one or two groups of —OH, alkoxy of 1 to 4 carbon atoms, thioalkoxy of 1 to 4 carbon atoms; Sp is a straight or branched-chain divalent or trivalent alkyl radical of 1 to 18 carbon atoms, divalent or trivalent aryl or heteroaryl radical, divalent or trivalent cycloalkyl of 3 to 18 carbon atoms or heterocycloalkyl radical, divalent or trivalent aryl- or heteroaryl-alkyl (C.sub.1-C.sub.18) radical, divalent or trivalent cycloalkyl- or heterocyclo-alkyl-alkyl (C.sub.1-C.sub.18) radical or divalent or trivalent unsaturated alkyl radical of 2 to 18 carbon atoms, wherein heteroaryl is furyl, thienyl, N-methylpyrrolyl, pyridinyl, N-methylimidazolyl, oxazolyl, pyrimidinyl, quinolyl, isoquinolyl, N-methylcarbazoyl, aminocoumarinyl, or phenazinyl and wherein if Sp is a trivalent radical, it can be additionally substituted by dialkylamino of 1 to 5 carbon atoms, alkoxy of 1 to 5 carbon atoms, hydroxy, or alkylthio of 1 to 5 carbon atoms groups; and Q is selected from the group consisting of —NNHCO—, —NNHCS—, and —NNHCONH—.

17. The bilinker carboxylic acid intermediate of claim 16, wherein Alk.sup.1 is a branched or unbranched alkylene chain of 2 to 5 carbon atoms.

18. The bilinker carboxylic acid intermediate of claim 16, wherein Alk.sup.1 is a branched or unbranched alkylene chain of 3 carbon atoms.

19. The bilinker carboxylic acid intermediate of claim 16, wherein Sp.sup.1 is an oxygen atom.

20. The bilinker carboxylic acid intermediate of claim 16, wherein Z.sup.1 is alkyl of 1 to 3 carbon atoms.

21. The bilinker carboxylic acid intermediate of claim 16, wherein Z.sup.1 is methyl.

22. The bilinker carboxylic acid intermediate of claim 16, wherein Ar is selected from the group consisting of 1, 2-phenylene, 1,3-phenylene, 1,4-phenylene, 1,2-naphthylidene, 1,3-naphthylidene, 1,4-naphthylidene, 1,5-naphthylidene, 1,6-naphthylidene, 1,7-naphthylidene, 1,8-naphthylidene, 2,3-naphthylidene, 2,6-naphthylidene, and 2,7-naphthylidene.

23. The bilinker carboxylic acid intermediate of claim 16, wherein Ar is 1,4-phenylene.

24. The bilinker carboxylic acid intermediate of claim 16, wherein Q is —NNHCO—.

25. The bilinker carboxylic acid intermediate of claim 16, wherein Sp is a straight or branched-chain divalent or trivalent alkyl radical of 1 to 12 carbon atoms.

26. The bilinker carboxylic acid intermediate of claim 16, wherein Sp is a straight or branched-chain divalent or trivalent alkyl radical of 1 to 6 carbon atoms.

27. The bilinker carboxylic acid intermediate of claim 16, wherein Sp is a straight or branched-chain divalent or trivalent alkyl radical of 4 carbon atoms.

28. The bilinker carboxylic acid intermediate of claim 16, having the formula: ##STR00073##

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) The process for the preparation of calicheamicin derivatives of Formula I and tri and bifunctional linker intermediates useful in the preparation of said derivatives of the present invention are described in the following reaction Schemes I and II.

(2) ##STR00059##

(3) In accordance with Scheme I, a carboxylic acid 1 wherein Alk.sup.1, Sp.sup.1, Ar and Z.sup.1 are hereinbefore defined, found in U.S. Pat. No. 5,773,001, which is hereby incorporated herein by reference, are condensed with mercapto compound 2 where Sp and Q are hereinbefore defined in an alcoholic solvent with a boiling point of less than about 100° C. in the presence of an alkyl carboxylic acid in a about 5% acetic acid at about 20° to about 70° C. for about 1 to about 24 hours, to afford bilinker-carboxylic acid 3 wherein Alk.sup.1, Sp.sup.1, Ar, Q, Sp and Z.sup.1 are as defined above.

(4) Bilinker-carboxylic acid 3 is reacted with N-hydroxysuccinimide, 2,3,5,6-tetrafluorophenol, pentafluorophenol, 4-nitrophenol, 2,4-dinitrophenol, or N-hydroxysulfosuccinimide in the presence of 1,3-dicyclohexylcarbodiimide (DCC), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDCI), or other carbodiimide or N,N′-disuccinimdyl carbonate in an inert solvent such as dichloromethane, tetrahydrofuran, dioxane, or acetonitrile containing 0-50% DMF or DMF to generate trilinker-activated ester 4 where Z is selected from the group consisting of

(5) ##STR00060##

(6) For example, reaction of bilinker-carboxylic acid 3 with a coupling agent, such as 1,3-dicyclohexylcarbodiimide (DCC) or 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and N-hydroxysuccinimide or other comparable carboxyl-activating group in an inert solvent, such as N,N-dimethylformamide (DMF), tetrahydrofuran, dioxane or acetonitrile, leads to the formation of a trilinker-activated ester 4, such as the N-hydroxysuccinimide ester described herein. Preferred is N-hydroxysuccinimide, DCC at ambient temperature in dioxane. A preferred solvent mixture is acetonitrile containing 0-50% DMF. Reaction of the bilinker-carboxylic acid 3 with N-hydroxysuccinimide, 2,3,5,6-tetrafluorophenol, pentafluorophenol, 4-nitrophenol, 2,4-dinitrophenol, or N-hydroxysulfosuccinimide in the presence of 1,3-dicyclohexylcarbodiimide (DCC), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDCI), or other carbodiimide in an inert solvent such as dioxane or acetonitrile containing 0-50% N,N-dimethylformamide (DMF) leads to the formation of a trilinker-activated ester 4. The trilinker-activated ester 4 can be isolated by removal of the volatile solvents and further purified by reverse or normal phase chromatography on an inert support which includes silica-60.

(7) Trilinker-activated ester 4 is first reacted with an alkali metal carbonate which includes but is not limited to sodium carbonate and forms the sodium salt of trilinker-activated ester 4 in acetonitrile by heating at gentle reflux. Further reaction of the sodium salt of trilinker-activated ester 4 with methyltrithioantitumor antibiotic 5 at about −15° C. in an inert organic solvent, preferably acetonitrile gives activated ester 6 wherein Z, Alk.sup.1, Sp.sup.1, Ar, Z.sup.1, Q, Sp and W′ are hereinbefore defined. In particular, N-acetyl-LL-E33288 γ.sub.1.sup.I is the preferred methyltrithioantitumor antibiotic 5. Preferred is the reaction in acetonitrile at about 0° C. Optionally an organic base may replace the alkali metal carbonate which preferably includes triethylamine, in acetonitrile at about 0° C.

(8) As further described in Scheme II, reaction of bilinker-carboxylic 3 prepared by condensation of carboxylic acid 1 wherein Alk.sup.1, Sp.sup.1, Ar and Z.sup.1 are hereinbefore defined, with mercapto compound 2 according to scheme I, is reacted with methyltrithioantitumor antibiotic 5 in the presence of triethylamine in N,N-dimethylformamide (DMF) at about −5° C. affords intermediate 7 which is further converted to trilinker-activated ester 6 by reaction with N-hydroxysuccinimide, 2,3,5,6-tetrafluorophenol, pentafluorophenol, 4-nitrophenol, 2,4-dinitrophenol, or N-hydroxysulfosuccinimide in the presence of 1,3-dicyclohexylcarbodiimide (DCC), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDCI), or other carbodiimide or N,N′-disuccinimdyl carbonate in an inert solvent mixture of DMF and acetonitrile which is then purified preferably by chromatography to afford antitumor antibiotics of Formula (I).

(9) ##STR00061##

(10) The following examples are presented to illustrate certain embodiments of the present invention, but should not be construed as limiting the scope of this invention. Those skilled in the art will readily understand that known variations of the conditions of the following preparative procedures can be used to prepare these compounds.

EXAMPLE 1

Butanoic acid, 3-mercapto-3-methyl-,2[(E)-1-[4-(4-hydroxy-4-oxobutoxy)phenyl]ethylidene]hydrazide

(11) ##STR00062##

(12) To a stirred mixture of 0.5 g [3.4 mmol] of 3-methyl-3-mercapto-butanoic acid hydrazide in 5.0 ml of methanol is rapidly added 0.91 g [4.1 mmol] of 4-(4-acetylphenoxy)-butanoic acid followed by an additional 10 ml of methanol and 1.5 ml of acetic acid and stirring continued for 24 hours. The reaction mixture is filtered and the solid washed with 100 ml of methanol to give 0.78 g of the title compound as a solid.

EXAMPLE 2

Butanoic acid, 3-mercapto-3-methyl-,2-[(E)-1-[4-(4-hydroxy-4-oxobutoxy)phenyl]ethylidene]hydrazide

(13) ##STR00063##

(14) A mixture of 3-methyl-3-mercapto-butanoic acid hydrazide (4.0 g, 27 mmol), 4-(4-acetylphenoxy)-butanoic acid (5.0 g, 22.5 mmol) and acetic acid (7.5 mL) in methyl alcohol (75 mL) is heated at about 45° C. for about 7 h. The mixture is allowed to cool to room temperature. The white solid (7.12 g, 90%) is collected on a Buchner funnel and washed with MeOH (2×10 mL). .sup.1H NMR (DMSO-d.sub.6): δ (ppm) 12.14 (s, 1H), 10.37 and 10.21 (s, 1H), 7.74-7.70 (m, 2H), 6.97-6.95 (m, 2H), 4.04 (t, 2H), 3.09 and 3.04 (s, 2H), 2.66 (s, 1H), 2.41-2.37 (t, 2H), 2.22 and 2.20 (s, 3H), 1.97-1.93 (m, 2H), 1.8 (s, 3H), 1.47 (s, 3H). MS: 375 (M.sup.++Na).

EXAMPLE 3

Butanoic acid, 3-mercapto-3-methyl-,2-[(E)-1-[4-[4-[(2,5-dioxo-1-pyrolidinyl)oxy]-4-oxobutoxy]phenyl]ethylidene]hydrazide

(15) ##STR00064##

(16) To a mixture of 0.5 g [1.42 mmol] of butanoic acid, 3-mercapto-3-methyl-,2-[(E)-1-[4-(4-hydroxy-4-oxobutoxy)phenyl]ethylidene]hydrazide (Example 1 or 2) and 0.22 g [1.89 mmol] of N-hydroxysuccinimide is added 10 ml of N,N-dimethylformamide followed by the rapid addition of 0.70 g [3.65 mmol] of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and the mixture stirred at room temperature for 3 hours. The reaction mixture is concentrated in vacuo to a residue which is partitioned between ethyl acetate and water. The separated organic layer is washed with water, saturated sodium chloride and dried (MgSO.sub.4). The organic layer is evaporated in vacuo to give an oily residue which crystallized from ethyl acetate-hexane affording 0.21 g of the title compound as a colorless solid.

EXAMPLE 4

Butanoic acid, 3-mercapto-3-methyl-,2-[(E)-1-[4-[4-[(2,5-dioxo-1-pyrrolidinyl)oxy]-4-oxobutoxyl]phenyl]ethylidene]hydrazide

(17) ##STR00065##

(18) A mixture of butanoic acid, 3-mercapto-3-methyl-,2-[(E)-1-[4-(4-hydroxy-4-oxobutoxy)phenyl]ethylidene]hydrazide (Examples 1 or 2) (3.69 g, 10.48 mmol) and N-hydroxysuccinimide (1.386 g, 12.05 mmol) is suspended in dioxane (60 mL), DCC (2.482 g, 12.05 mmol) in dioxane (30 mL) is added dropwise over 15 min. The mixture is stirred at room temperature for 24 h. The precipitated dicyclohexylurea is filtered off and washed with dioxane (2×10 mL). The filtrate is concentrated to about 50 mL and while stirring, water (250 mL) is added. The resulting white solid is collected on a Buchner funnel, washed with water (2×50 mL), and dried in vacuo at room temperature. To this white solid is added MeCN (60 mL) and the mixture is heated at 50° C. until it became solution, isopropyl alcohol (IPA) (400 mL) is added. The mixture is then cooled to 0-5° C. for 2 h. The solid is collected on a Buchner funnel, washed with cold IPA (2×20 mL) an dried in vacuo to afford the product of the example as a white solid (3.58 g, 70%). MS: 450 (M.sup.++1).

EXAMPLE 5

Butanoic acid, 3-mercapto-3-methyl-,2-[(E)-1-[4-[4-[(2,5-dioxo-1-pyrrolidinyl)oxy]-4-oxobutoxy]phenyl]ethylidene]hydrazide condensed with N-acetyl-LL-E33288γ1I

(19) ##STR00066##

(20) To a stirred solution of 0.505 g [1.12 mmol]butanoic acid, 3-mercapto-3-methyl-,2-[(E)-1-[4-[4-[(2,5-dioxo-1-pyrrolidinyl)oxy]-4-oxobutoxy]phenyl]ethylidene]hydrazide (Example 4) in 50 ml of acetonitrile is added 0.123 g [1.16 mmol] of sodium carbonate followed by heating at gentle reflux for 1 hour, cooled to room temperature and filtered. The filtrate is cooled to −15° C. and a solution of 1.4969 g [1.1 mmol] of N-acetyl-LL-E33288 γ.sub.1.sup.I in 5 ml of acetonitrile added slowly by dropwise addition over 20 minutes and stirring continued for about 1.5 hours. The reaction mixture is allowed to warm to room temperature and stirred for about 3 hours. The volatiles are evaporated in vacuo to a residue which is stored in a freezer. To the residue is added 25 ml of ethyl acetate followed by storage in a freezer for about 1 hour. The reaction mixture is filtered and the ethyl acetate evaporated to a residue which is dissolved in 10 ml of ethyl acetate and applied to a column of 110 g of silica gel. The column is eluted with 1-5% methyl alcohol in ethyl acetate to give 0.322 g of the desired product having 65.27% purity as determined by HPLC.

EXAMPLE 6

Butanoic acid, 3-mercapto-3-methyl-,2-[(E)-1-[4-[4-[(2,5-dioxo-1-pyrrolidinyl)oxy]-4-oxobutoxy]phenyl]ethylidene]hydrazide condensed with N-acetyl-LL-E33288γ1I

(21) ##STR00067##

(22) A solution of butanoic acid, 3-mercapto-3-methyl-,2-[(E)-1-[4-[4-[(2,5-dioxo-1-pyrrolidinyl)oxy]-4-oxobutoxy]phenyl]ethylidene]hydrazide (450 mg, 1 mmol) (Example 4) in CH.sub.3CN (100 mL) containing Et.sub.3N (0.35 mL) is treated with a solution of N-acetyl-LL-E33288 γ.sub.1.sup.I (500 mg, 0.355 mmol) in CH.sub.3CN (100 mL) at 0-5° C. The mixture is then stirred for another 1 h while cooling with a ice-bath. The solvent is removed and the residue is purified on a silica gel column eluting with CH.sub.2Cl.sub.2-MeOH to afford the product of the example (340 mg, 54%) as a white solid. MS: 1780 (M.sup.++1)

EXAMPLE 7

Butanoic acid, 3-mercapto-3-methyl-,2-[(E)-1-[4-(4-hydroxy-4-oxobutoxy)phenyl]ethylidene]hydrazide condensed with N-acetyl-LL-E33288γ1I

(23) ##STR00068##

(24) To a stirring solution of N-acetyl-LL-E33288 γ.sub.1.sup.I (200 mg, 0.142 mmol) in 10 ml acetonitrile/ethyl acetate (1:1) at −5° C. is added in 1 ml aliquots every 10 min a solution of butanoic acid, 3-mercapto-3-methyl-,2-[(E)-1-[4-(4-hydroxy-4-oxobutoxy)phenyl]ethylidene]hydrazide (150 mg, 0.43 mmol) (Examples 1 or 2) in 10 ml acetonitrile/ethyl acetate (1:1) and 0.06 ml triethyl amine. The solution is stirred for two hours at −5° C. after the last addition of the butanoic acid, 3-mercapto-3-methyl-,2-[(E)-1-[4-(4-hydroxy-4-oxobutoxy)phenyl]ethylidene]hydrazide solution. The solvent was removed under reduced pressure and the residue is purified on a silica gel column eluting with CH.sub.2Cl.sub.2-MeOH to afford the product of the example as a white solid. MS 1684 (M.sup.++1)

EXAMPLE 8

Butanoic acid, 3-mercapto-3-methyl-,2-[(E)-1-[4-[4-[(2,5-dioxo-1-pyrrolidinyl)oxy]-4-oxobutoxy]phenyl]ethylidene]hydrazide condensed with N-acetyl-LL-E33288γ1I

(25) To a stirring solution of butanoic acid, 3-mercapto-3-methyl-,2[(E)-1-[4-(4-hydroxy-4-oxobutoxy)phenyl]ethylidene]hydrazide with N-acetyl-LL-E33288γ.sub.1.sup.I (100 mg, 0.059 mmol) in 0.5 mL of DMF and 1.8 mL of acetonitrile at 25° C. is added N-hydroxysuccinimide (236 mg, 2.05 mmol) and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (160 mg 0.835 mmol). Following the addition, the solution is stirred for one hour at 25° C. The acetonitrile is removed under reduced pressure and the resulting DMF solution is added to 3 mL of stirring water giving a precipitate. The precipitate is filtered, dried and purified on a silica gel column eluting with CH.sub.2Cl.sub.2-isopropyl alcohol giving the product of the example (53 mg, 50%) obtained as a white solid. MS: 1780 (M.sup.++1)