METHODS, COMPOUNDS, COMPOSITIONS AND VEHICLES FOR DELIVERING 3-AMINO-1-PROPANESULFONIC ACID

Abstract

The invention relates to methods, compounds, compositions and vehicles for delivering 3-amino-1-propanesulfonic acid (3APS) in a subject, preferably a human subject. The invention encompasses compound that will yield or generate 3APS, either in vitro or in vivo. Preferred compounds include amino acid prodrugs of 3APS for use, including but not limited to the prevention and treatment of Alzheimer's disease

Claims

1. A compound selected from the group consisting of: a) a compound of Formula I:
B-L-A   (I) wherein B is a pharmacokinetic modulating moiety, which is optionally also bonded to A directly or indirectly through a further linking group L; A is a 3-amino-1-propanesulfonic acid moiety; and L is a cleavable linkage for covalently and dissociably coupling B to A via the NH.sub.2 group, whereby L can be a direct bond or additional chemical structure providing a cleavable linkage, or a pharmaceutically acceptable salt thereof; b) a compound of Formula I-A: ##STR00151## wherein, R.sup.x and R.sup.y are independently selected from hydrogen and a protecting group, wherein R.sup.x and R.sup.y are not both hydrogen; and L.sup.1 and L.sup.2 are each a cleavable linkage; wherein when R.sup.x is H, L.sup.1 is absent, and when R.sup.y is H, then L.sup.2 is absent, or a pharmaceutically acceptable salt thereof; c) a compound of Formula VII: ##STR00152## wherein, f) a compound of Formula X: ##STR00153## wherein, R.sup.10 is a residue of a carbohydrate, a carbohydrate derivative or a carbohydrate-derived polyol, e.g., a C.sub.5-6 saturated or partially or completely unsaturated cycloalkyl group, optionally and preferably containing an —O— group, which is substituted by 3 to 5 substituents, each independently selected from —OH, —OAc, —CH.sub.2OH, —OCH.sub.3, —CH.sub.2OAc and ═O. L is a linking moiety or is absent, e.g., an alkyl group, which may be saturated or unsaturated, preferably a lower alkyl group, which is optionally interrupted by one or more —O— and/or —NH— groups, and is optionally substituted by one or more ═O, —OH, and/or —NH.sub.2 groups, or a pharmaceutically acceptable salt thereof; g) a compound of Formula XI: ##STR00154## wherein, R.sup.11 is a hydrogen or a substituted or unsubstituted group selected from C.sub.1-C.sub.12 alkyl, C.sub.2-C.sub.12 alkenyl, C.sub.2-C.sub.12 alkynyl, C.sub.3-C.sub.15 cycloalkyl, C.sub.3-C.sub.15 heterocycloalkyl, C.sub.6-C.sub.15 aryl, C.sub.5-C.sub.15 heteroaryl, C(O)R.sup.12, and C(O)OR.sup.13; and R.sup.12 and R.sup.13 are independently selected from substituted or unsubstituted C.sub.1-C.sub.12 alkyl, C.sub.2-C.sub.12 alkenyl, C.sub.2-C.sub.12 alkynyl, C.sub.3-C.sub.15 cycloalkyl, C.sub.3-C.sub.15 heterocycloalkyl, C.sub.6-C.sub.15 aryl, and C.sub.5-C.sub.15 heteroaryl, or a pharmaceutically acceptable salt thereof; h) a compound of Formula XII: ##STR00155## wherein, D is a carbonyl, an amino acid residue, or a substituted methylene group; and R.sup.5 is a substituted or unsubstituted group selected from C.sub.1-C.sub.12alkyl, C.sub.2-C.sub.12 alkenyl, C.sub.2-C.sub.12 alkynyl, C.sub.3-C.sub.15 cycloalkyl, C.sub.3-C.sub.15 heterocycloalkyl, C.sub.6-C.sub.15 aryl, C.sub.5-C.sub.15 heteroaryl, NH(C.sub.1-C.sub.6 alkyl), N(C.sub.1-C.sub.6 alkyl).sub.2, and C(O)(C.sub.1-C.sub.6 alkyl); R.sup.6 is a hydrogen or a substituted or unsubstituted group selected from C(O)NH.sub.2, C(O)NH(C.sub.1-C.sub.6 alkyl), C(O)N(C.sub.1-C.sub.6 alkyl).sub.2, and C(O)(C.sub.1-C.sub.6 alkyl); or R.sup.5 and R.sup.6 are taken together with the adjacent carbon atom to form a substituted or unsubstituted C.sub.3-C.sub.12 heterocycloalkyl; M is selected from the group consisting of oxygen, sulfur, nitrogen or absent, or a pharmaceutically acceptable salt thereof; d) a compound of Formula VIII: ##STR00156## wherein, R.sup.7 is a substituted or unsubstituted group selected from C.sub.1-C.sub.12 alkyl, C.sub.2-C.sub.12 alkenyl, C.sub.2-C.sub.12 alkynyl, C.sub.3-C.sub.15 cycloalkyl, C.sub.3-C.sub.15 heterocycloalkyl, C.sub.6-C.sub.15 aryl, C.sub.5-C.sub.15 heteroaryl, C.sub.7-C.sub.12 arylalkyl, C.sub.7-C.sub.12 heteroarylalkyl, and combinations thereof, or a pharmaceutically acceptable salt thereof; e) a compound of Formula IX: ##STR00157## wherein, R.sup.8 is a substituted or unsubstituted group selected from C.sub.1-C.sub.12 alkyl, C.sub.2-C.sub.12 alkenyl, C.sub.2-C.sub.12 alkynyl, C.sub.3-C.sub.15 cycloalkyl, C.sub.3-C.sub.15 heterocycloalkyl, C.sub.6-C.sub.15 aryl, C.sub.5-C.sub.15 heteroaryl; and R.sup.9 is a hydrogen or a substituted or unsubstituted C(O)(C.sub.1-C.sub.6 alkyl), C(O)NH.sub.2, C(O)NH(C.sub.1-C.sub.6 alkyl), or C(O)N(C.sub.1-C.sub.6 alkyl).sub.2; or R.sup.8 and R.sup.9 are taken together with the adjacent carbon atom to form a substituted or unsubstituted C.sub.3-C.sub.12 heterocycloalkyl, or a pharmaceutically acceptable salt thereof; X is selected from O, NH, and S, or a pharmaceutically acceptable salt thereof; i) a compound of Formula XIII: ##STR00158## wherein, R.sup.15 and R.sup.16 are independently selected from a hydrogen or a substituted or unsubstituted group selected from C.sub.1-C.sub.12 alkyl, C.sub.2-C.sub.12 alkenyl, C.sub.2-C.sub.12 alkynyl, C.sub.3-C.sub.15 cycloalkyl, C.sub.3-C.sub.15 heterocycloalkyl, C.sub.6-C.sub.15 aryl, and C.sub.5-C.sub.15 heteroaryl, or a pharmaceutically acceptable salt thereof; and j) a compound of Formula I-P:
A-(L.sup.x-A).sub.p-L.sup.x-A   (I-P) wherein: A is 3-amino-1-propanesulfonic acid moiety; L.sup.x is a cleavable linkage for covalently and dissociably coupling together two adjacent 3APS moieties, and p is 0, or an integer number which may vary from 1 to 5, e.g. 2, 3, 4, or 5; or a pharmaceutically acceptable salt thereof.

2. The compound of claim 1, wherein the compound of Formula XII is a compound of Formula XII-A: ##STR00159## wherein, R.sup.14 is a substituted or unsubstituted group selected from C.sub.1-C.sub.12 alkyl, C.sub.2-C.sub.12 alkenyl, C.sub.2-C.sub.12 alkynyl, C.sub.3-C.sub.15 cycloalkyl, C.sub.3-C.sub.15 heterocycloalkyl, C.sub.6-C.sub.15 aryl, C.sub.5-C.sub.15 heteroaryl, or a pharmaceutically acceptable salt thereof.

3. The compound of claim 1, wherein said compound of Formula I-P is selected from the group consisting of: a) a compound of Formula I-P2:
L.sup.y(A).sub.m   (I-P2) wherein, m is an integer from 2 to 5; A is 3-amino-1-propanesulfonic acid moiety; L.sup.y is a multivalent carrier moiety for covalently and dissociably coupling from two to five A moieties, either at the amino or sulfonic acid end of A, or a pharmaceutically acceptable salt thereof; b) a compound of Formula I-C: ##STR00160## wherein, L.sup.3 is bivalent linker which connects two molecules of 3APS at their amino groups either using the same or different linkages as defined herein, including, but not limited to, amide linkage and carbamate linkage, or a pharmaceutically acceptable salt thereof; c) a compound of Formula I-D: ##STR00161## wherein, L.sup.4 is a bivalent linker which connects two molecules of 3APS at their sulfonic acid groups either using the same or different linkages as defined herein, including, but not limited to, ester linkage or anhydride linkage where X is oxygen, or sulfonamide linkage where X is nitrogen (NH, or NR), or thiosulfonate linkage where X is sulfur, P is hydrogen or a N-protecting group, or a pharmaceutically acceptable salt thereof; and d) a compound of Formula I-E: ##STR00162## wherein, L.sup.5 is a bivalent linker which connects two molecules of 3APS, at amino group in one 3APS using a linkage as defined in Formula I-C, and at sulfonic acid group in the other 3APS using a linkage as defined in Formula I-D, P is hydrogen or a N-protecting group as defined herein, or a pharmaceutically acceptable salt thereof.

4. The compound of claim 1, wherein said compound is selected from the group consisting of: ##STR00163## ##STR00164## ##STR00165## ##STR00166## ##STR00167## ##STR00168## ##STR00169## ##STR00170## or a pharmaceutically acceptable salt thereof.

5. A method for treating Alzheimer's disease, mild cognitive impairment, Down's syndrome, Hereditary Cerebral Hemorrhage with Amyloidosis of the Dutch-Type, cerebral amyloid angiopathy, a degenerative dementia, a dementia of mixed vascular and degenerative origin, dementia associated with Parkinson's disease, dementia associated with progressive supranuclear palsy, dementia associated with cortical basal degeneration, or diffuse Lewy body type of Alzheimer's disease, comprising administering a therapeutically effective amount of a compound of claim 1 to a human subject in need thereof.

6. The method of claim 5, which is for treating Alzheimer's disease, mild cognitive impairment, cerebral amyloid angiopathy, or degenerative dementia.

7. The method of claim 6, which is for treating Alzheimer's disease.

8. The method of claim 5 wherein the compound is administered intratracheally, intranasally, ontologically, rectally, vaginally, or orally.

9. A pharmaceutical composition comprising a compound of claim 1 together with a pharmaceutically acceptable carrier.

10. The pharmaceutical composition of claim 9 which is suitable for oral administration.

11. The pharmaceutical composition of claim 9, which is in the form of a hard shell gelatin capsule, soft shell gelatin capsule, cachet, pill, tablet, lozenge, powder, granule, pellet, dragee, which is optionally enteric coated, a solution, an aqueous liquid suspension, a non-aqueous liquid suspension, an oil-in-water liquid emulsion, a water-in-oil liquid emulsion, an elixir, a syrup, or a pastille.

12. A process for converting a compound of claims 1 to 3-amino-1-propanesulfonic acid (3APS) comprising contacting said compound with plasma, blood and/or brain cells whereby said compound is metabolized to 3APS.

Description

EXAMPLES

[0301] The Examples set forth herein below provide exemplary syntheses of certain representative compounds of the invention. Also provided are exemplary methods for assaying the compounds of the invention for in vitro stability, microsomes metabolism and mouse bioavailability.

[0302] Unless otherwise indicated, all numbers expressing quantities of ingredients, reaction conditions, concentrations, properties, and so forth used in the specification and claims are to be understood as being modified in all instances by the term “about” At the very least, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the present specification and attached claims are approximations that may vary depending upon the properties sought to be obtained. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the embodiments are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contain certain errors resulting from variations in experiments, testing measurements, statistical analyses and such.

[0303] The present invention also relates to novel compounds and the synthesis thereof. The following detailed examples describe how to prepare the various compounds and/or perform the various processes of the invention and are to be construed as merely illustrative, and not limitations of the preceding disclosure in any way whatsoever. Those skilled in the art will promptly recognize appropriate variations from the procedures both as to reactants and as to reaction conditions and techniques. In some cases, the compounds may be commercially available.

Example 1-A: Chemical Synthesis of Amino Acid Prodrugs

[0304] Accordingly, the following examples are presented to illustrate how some amino acid prodrugs according to the invention compounds may be prepared.

Preparation of N-hydroxysuccinimide Ester

[0305] ##STR00129##

[0306] To a stirred solution of a N-Boc-protected amino acid or a carboxylic acid (10 mmol) in CH.sub.2Cl.sub.2 (100 mL) was added HBTU (N,N,N′,N′-Tetramethyl-O-(1H-benzotriazol-1-yl)uronium hexafluorophosphate, 4.17 g, 11 mmol) followed by addition of triethylamine (1.53 mL, 11 mmol) and N-hydroxysuccinimide (NHS, 1.26 g, 11 mmol). The reaction mixture was stirred at room temperature for 4 h, and then diluted with HCl (1 N) and EtOAc (ethyl acetate). The organic layer was isolated, dried over Na.sub.2SO.sub.4, and concentrated. The residual material was purified by flash chromatography on silica gel using hexanes-EtOAc as eluent to afford the corresponding N-hydroxysuccinimide ester in good yield (about 70 to 88%).

General Procedures for the Preparation of Amino Acid Prodrugs of 3-amino-1-propanesulfonic Acid (Procedures A to D):

[0307] Procedures A to D were used in different combinations, to produce exemplary compounds of the invention. Results for the preparation of Compounds A to Y using these procedures are summarized in Table 2 below.

Procedure A:

[0308] ##STR00130##

[0309] A solution of the N-hydroxysuccinimide ester of a N-Boc-protected amino acid or a carboxylic acid (48 mmol, 1.2 eq) in acetonitrile or acetone (50 mL) was added slowly to a solution of 3APS, 3-amino-1-propanesulfonic acid, 40 mmol, 1 eq in 2 N NaOH (sodium hydroxide, 23 mL, 1.2 eq). The reaction mixture was stirred at room temperature overnight. The mixture was evaporated to dryness. The residual material was stirred with Et.sub.2O (diethyl ether, 150 mL) at reflux for 1 h. After the mixture was cooled to room temperature, the solid material was filtered and dried in vacuo, and further purified according to one of the following work-up procedures: [0310] (i) The solid material was dissolved in water (25 mL). The solution was passed through a Dowex™ Marathon™ C ion-exchange column (strongly acidic, 110 g (5 eq), pre-washed). The strong acidic fractions were combined and treated with concentrated HCl (10 mL). The mixture was stirred at 50° C. for 30 minutes, and then was concentrated to dryness. The residual material was co-evaporated with EtOH (ethanol) to completely remove water. EtOH (100 mL) was added to the residue. The mixture was stirred at reflux for 1 h, and then cooled to room temperature. The solid material was collected by filtration. The solid material was dissolved in water (10 mL). The solution was added drop wise to EtOH (100 mL). The product slowly crystallized. The suspension was stirred at room temperature for 30 minutes. The solid material was collected by filtration and it was dried in a vacuum oven (60° C.). [0311] (ii) The solid material was dissolved in water (25 mL). The solution was passed through a Dowex™ Marathon™ C ion exchange column (strongly acidic, 110 g (5 eq), pre-washed). The strong acidic fractions were combined and evaporated under reduced pressure. The residue was purified using reverse-phase flash chromatography (Biotage™ SP-1, C18 column). For ester-containing compound, the final product was obtained after removal of the solvent from the corresponding fractions; otherwise go to (iii). [0312] (iii) The residual material from step (ii) above was stirred with 4N HCl (3 mL) at 50° C. for 1 h. A white solid precipitate appeared. After the mixture was cooled to room temperature, the solid material was collected by filtration, washed, and dried in vacuo, to provide the final product.

Procedure B:

[0313] To a stirred solution of a N-hydroxysuccinimide ester (3 mmol) in a mixture of H.sub.2O/tetrahydrofuran/CH.sub.3CN (10/10/10 mL) was added a solution of SAPS (as sodium salt) (3.3 mmol) in water (5 mL) followed by addition of 1M solution of potassium carbonate (3 mL). The reaction mixture was stirred for 2 h, followed by addition of EtOAc. The aqueous layer was isolated and concentrated to a residue. The residual material was purified by silica gel column using CH.sub.2Cl.sub.2-MeOH (80-20) as eluent to give the corresponding N-Boc-protected product. The purified N-Boc-protected product was dissolved in dichloromethane (CH.sub.2Cl.sub.2, 10 mL) followed by addition of TFA (trifluoroacetic acid, 5 mL). The reaction mixture was stirred for 2 h, and then concentrated under reduced pressure. The residual solid material was suspended in a minimum amount of ethanol and the mixture was stirred for 1 h under reflux. The mixture was cooled to room temperature. The solid material was collected by filtration, washed with ethanol, and dried under high vacuum to afford the final compound.

Procedure C:

[0314] To the purified product containing benzyl ether protection group from procedure A or B (3.5 mmol) in 2N HCl (500 mL) and MeOH (500 mL) was added 10% Pd/C (2.15 g). The mixture was stirred under hydrogen (1 atm) overnight. The suspension was filtered (Celite™. The filter cake was washed with water (2×25 mL). The filtrate and the washing were combined and evaporated under reduced pressure. The residual material was purified by reverse-phase HPLC (C18 column, 0-15% acetonitrile/water). The fractions containing the desired compound were combined and lyophilized, to give the final product.

Procedure D:

[0315] This procedure is used to produce prodrugs of Formulae I to VI having more than one amino acid coupled to 3APS. Step (i) or (ii) is repeated as necessary to obtain the desired compound.

##STR00131## [0316] (i) The product from Procedures A, B, or C is further reacted with another N-hydroxysuccinimide ester following Procedure A(i). [0317] (ii) The product from Procedures A, B, or C was further reacted with another N-hydroxysuccinimide ester following Procedure B.

TABLE-US-00006 TABLE 5 Synthesis and characterization of exemplary amino acid prodrugs according to the invention Synthetic NMR (ppm; 1H 500 MHz; 13C 125 MHz) ID Procedure MS (electrospray ionization) A1 A(i) 1H NMR (D2O) δ 1.55-1.61 (m, 2H), 2.40-2.48 (m, 2H), 2.92-3.01 (m, 2H), 3.04-3.14 (m, 2H), 3.95-3.98 (m, 1H), 7.11 (d, J = 6.8 Hz, 2H), 7.197.27 (m, 3H); 13C NMR (D2O) δ 23.76, 37.02, 38.21, 48.36, 54.79, 128.19, 129.33, 129.42, 134.01, 168.94; m/z 285 (M − 1). A2 A(i) 1H NMR (D2O) δ 0.87-0.90 (m, 6H), 1.83 (qt, J = 7.2 Hz, 2H), 2.02-2.09 (m, 1H), 2.79 (t, J = 7.8 Hz, 2H), 3.20-3.29 (m, 2H), 3.60 (d, J = 6.3 Hz, 2H); 13C NMR (D2O) δ 17.20, 17.77, 24.11, 30.00, 38.29, 48.63, 58.96, 169.35; m/z 237 (M − 1). A3 A(i) 1H NMR (D2O) δ 1.82 (qt, J = 7.2 Hz, 2H), 1.90-1.95 (m, 3H), 2.28-2.33 (m, 1H), 2.78 (t, J = 7.8 Hz, 2H), 3.22-3.33 (m, 4H), 4.21 (t, J = 7.1 Hz, 2H); 13C NMR (D2O) δ 23.95, 24.07, 29.85, 38.49, 46.57, 48.53, 60.00, 169.64; m/z 235 (M − 1). A4 A(ii) 1H NMR (D2O) δ 1.30 (qt, J = 8.1 Hz, 2H), 1.57 (qt, J = 7.8 Hz, 2H), 1.75-1.85 (m, 4H), 2.77-280 (m, 2H), 2.87 (t, J = 7.8 Hz, 2H), 3.17 (qt, J = 6.7 Hz, 1H), 3.31 (qt, J = 6.8 Hz, 1H), 3.83 (t, J = 6.6 Hz, 1H); 13C NMR (D2O) δ 21.47, 24.12, 30.49, 38.30, 39.18, 48.63, 53.28, 169.66; m/z 266 (M − 1). A5 B 1H NMR (DMSO-d6) δ 0.81 (d, J = 7.3 Hz, 3H), 7.84 (d, J = 7.3 Hz, 3H), 1.5 (m, 1H), 1.60 (m, 2H), 1.82 (m, 2H), 2.80 (m, 2H), 3.20-3.30 (m, 2H), 3.82 (t, J = 7.3 Hz, 1H); 13C NMR (DMSO-d6) δ 21.48, 21.78, 24.17, 38.42, 40.08, 48.66, 52.35, 170.53; m/z 251 (M − 1). A6 A(i) 1H NMR (D2O) δ 1.84 (m, 2H), 1.99 (s, 3H), 2.04 (m, 2H), 2.47 (m, 2H), 2.80 (m, 2H), 3.24 (t, J = 6.6 Hz, 2H), 3.94 (t, J = 6.6 Hz, 2H); 13C NMR (D2O) δ 14.18, 24.07, 28.44, 30.09, 38.41, 48.61, 52.66, 169.46; m/z 269 (M − 1). A7 B and C 1H NMR (D2O) δ 1.81 (m, 2H), 2.80 (m, 2H), 3.23 (m, 2H), 3.80 (m, 2H), 3.97 (t, J = 5.0 Hz, 1H); 13C NMR (D2O) δ 24.10, 38.39, 48.55, 54.85, 60.44, 167.97; m/z 225 (M − 1). A8 A(i) 1H NMR (D2O) δ 3.90 (q, 1H, J = 7 Hz), 3.23 (t, 2H, J = 7 Hz), 2.78 (m, 2H), 1.82 (m, 2H), 1.38 (d, 3H, J = 7 Hz); 13C NMR (D2O) δ 170.90, 49.30, 48.55, 38.28, 24.10, 16.65; m/z 209 (M − 1). A9 A(i) 1H NMR (D2O) δ 3.90 (q, 1H, J = 7 Hz), 3.23 (t, 2H, J = 7 Hz), 2.78 (m, 2H), 1.82 (m, 2H), 1.38 (d, 3H, J = 7 Hz); 13C NMR (D2O) δ 170.90, 49.30, 48.55, 38.28, 24.10, 16.65; m/z 209 (M − 1). A10 B 1H NMR (D2O) δ 1.82 (m, 2H), 2.80 (m, 2H), 3.25 (m, 2H). 3.67 (s, 2H); 13C NMR (D2O) δ 24.13, 38.26, 40.57, 48.55, 167.08; m/z 195 (M − 1). A11 A(i) 1H NMR (D2O) δ 0.80 (t, 3H, J = 7.3 Hz), 0.86 (d, 3H, J = 6.8 Hz), 1.12 (m, 1H), 1.40 (m, 1H), 1.83 (m, 3H), 2.79 (m, 2H), 3.25 (m, 2H), 3.68 (d, 1H, J = 5.9 Hz); 13C NMR (D2O) δ 10.59, 14.22, 24.11, 24.37, 36.38, 38.29, 48.64, 58.00, 169.35; m/z 251 (M − 1). A12 A(i) 1H NMR (D2O) δ 1.84 (m, 2H), 1.99 (s, 3H), 2.04 (m, 2H), 2.47 (m, 2H), 2.80 (m, 2H), 3.25 (t, J = 7.3 Hz, 2H), 3.94 (t, J = 6.6 Hz, 1H); 13C NMR (D2O) δ 14.18, 24.06, 28.42, 30.07, 38.41, 48.60, 52.66, 169.42; m/z 269 (M − 1). A13 A(i) 1H NMR (D2O) δ 1.70 (m, 2H), 2.64 (m, 2H), 3.15 (m, 1H), 3.22 (m, 3H), 4.06 (t, J = 6.3 Hz, 1H), 7.30 (s, 1H), 8.55 (d, J = 1.5 Hz, 1H); 13C NMR (D2O) δ 23.94, 26.27, 38.36, 48.43, 52.59, 118.40, 126.36, 134.60, 167.96; m/z 275 (M − 1). A14 A(i) 1H NMR (D2O) δ 1.46 (s, 6H), 1.83 (m, 2H), 2.77 (m, 2H), 3.23 (t, J = 6.6 Hz, 2H); 13C NMR (D2O) δ 23.44, 24.08, 38.54, 48.61, 57.21, 173.20; m/z 223 (M − 1). A15 A(i) 1H NMR (D2O) δ 1.74 (m, 2H), 2.59 (m, 2H), 3.15 (m, 1H), 3.23 (m, 1H), 4.95 (s, 1H), 7.38 (m, 5H); 13C NMR (D2O) δ 24.00, 38.35, 48.38, 56.84, 128.05, 129.87, 130.52, 132.46, 168.90; m/z 271 (M − 1). A16 A(i) 1H NMR (D2O) δ 1.49 (m, 2H), 2.34 (m, 2H), 2.98 (m, 2H), 3.21 (m, 2H), 4.01 (m, 1H), 7.05 (t, 1H, J = 7.3 Hz), 7.14 (m, 2H), 7.39 (d, 1H, J = 8.3 Hz), 7.47 (m, 1H); 13C NMR (D2O) δ 23.60, 27.14, 38.32, 48.16, 54.12, 106.83, 112.32, 118.23, 119.70, 122.35, 125.18, 126.63, 136.37, 139.57; m/z 324 (M − 1). A17 A(iii) 1H NMR (D2O) δ 1.66 (m, 2H), 2.58 (m, 2H), and 2.92 (m, 1H), 3.04 (m, 2H), 3.17 (m, 1H), then C 3.95 (t, 1H, J = 6.3 Hz), 6.77 (d, 2H, J 8.8 Hz), 7.02 (d, 2H, J = 8.3 Hz); 13C NMR (D2O) δ 23.91, 36.29, 38.25, 48.42, 54.95, 116.07, 125.88, 130.91, 155.29, 169.56; m/z 301 (M − 1). A18 B 1H NMR (D2O) δ 1.77 (m, 2H), 2.74 (m, 2H), 3.19 (, m2H), 3.75 (m, 2H), 4.05 (m, 1H), 4.42 & 4.65 (AB, J = 12.2 Hz, 2H), 7.26-7.33 (m, 5H); 13C NMR (D2O) δ 24.10, 38.43, 53.23, 67.39, 73.28, 128.63, 128.67, 128.96, 136.86, 167.55; m/z 315 (M − 1). A19 A(ii) 1H NMR (D2O) δ 7.3-7.2 (m, 5H), 5.05 (s, 2H), 3.83 (t, J = 6.7 Hz, 1H), 3.21 (qn, J = 7 Hz, 1H), 3.08 (qn, J = 7 Hz, 1H), 2.78 (t, J = 7.8 Hz, 2H), 2.45 (t, J = 7 Hz, 2H), 2.05 (q, J = 7 Hz, 2H), 1.78 (m, 2H); m/z 357 (M − 1). A20 B 1H NMR (D2O) δ 1.78-1.85 (m, 4H), 2.24 (t, J = 7.5 Hz, 2H), 2.79 (m, 2H), 2.88 (t, J = 7.8 Hz, 2H), 3.18 (t, J = 7.0 Hz, 2H). 13C NMR (D2O) δ 23.21, 24.16, 32.70, 38.16, 38.98, 48.65, 175.06; m/z 223 (M − 1). A22 1H NMR (D2O) δ 1.84 (qn, 2H, J = 7 Hz), 2.78 (dd, 2H, J = 8.0, 6 Hz), 2.85 (ABX, 2H, J = 5.5, 7.3, 16.8 Hz), 3.24 (m, 2H), 3.61 (dd, 1H, J = 5.5, 7.3 Hz); 13C NMR (D2O) δ 24.05, 35.42, 38.46, 48.53, 50.04, 169, 171. A28 1H NMR (D2O) δ 0.8-0.9 (m, 12H), 1.81 (m, 1H), 1.88 (m, 1H), 2.09 (m, 2H), 2.77 (t, 2H, J = 8.0 Hz), 3.20 (t, 2H, J = 6.6 Hz), 3.73 (d, 1H, J = 6.1 Hz), 3.87 (d, 1H, J = 8.9 Hz); 13C NMR (D2O) δ 16.93, 17.82, 18.36, 24.21, 29.77, 30.27, 38.08, 48.72, 58.42, 60.66, 169.45, 173.07

Example 1-B: Chemical Synthesis of Carbamate Prodrugs

[0318] Accordingly, the following examples are presented to illustrate how some carbamate prodrugs according to the invention compounds may be prepared.

General Synthetic Procedures

Procedure A:

Preparation of Compound C1 Sodium Salt (3-(p-acetyloxybenzyloxycarbonyl)amino-1-propanesulfonic Acid Sodium Salt)

[0319] ##STR00132##

[0320] Step 1: Acetyl chloride (3.0 mL, 42 mmol, 1 eq.) was added to a mixture of 4-hydroxybenzylalcohol (5.3 g, 42 mmol), sodium hydroxide (1.7 g, 42 mmol, 1 eq.) and tetrabutylammonium hydrogen sulfate (7 g, 0.5 eq.) in dioxane (100 mL). The reaction mixture was stirred at room temperature for 4 hours and the solvent was evaporated. The residue was dissolved in water and the aqueous phase was extracted with EtOAc (3 times). Combined organic extracts were washed with brine, dried and concentrated to give colorless oil. Purification (flash chromatography; hexane/EtOAc, gradient mode) provided the corresponding monoacetate (2.2 g, 32%).

[0321] Step 2: Anhydrous pyridine (1.1 mL, 13 mmol, 1 eq,) was added drop wise to a stirred mixture of p-nitrophenyl chloroformate (4.0 g, 20 mmol, 1.5 eq.) and the monoacetate (from step 1: 2.2 g, 13 mmol) in dry tetrahydrofuran (THF, 25 mL). A white precipitate was formed. The reaction mixture was stirred at room temperature for 1 hour. The solid material was removed by filtration, and washed with THF. The filtrate and the washing were combined; and the solvent was removed in vacuo. The residual material was purified by flash chromatography (hexanes/EtOAc, 80/20) to provide the corresponding carbonate (2.8 g, 62%).

[0322] Step 3: The carbonate prepared in the step 2 (2.2 g, 6.7 mmol, 2 eq.) was added to a mixture of 3-amino-1-propanesulfonic acid sodium salt (538 mg, 3.32 mmol) and triethylamine (0.90 ml, 6.7 mmol, 2 eq.) in dry N,N-dimethylformamide (DMF, 10 mL). The reaction mixture was stirred at room temperature overnight. Solvent was removed by evaporation. The residue was partitioned between EtOAc and water. The aqueous phase was washed twice with EtOAc, and then lyophilized. HPLC purification (acetonitrile/water, 20/80 to 90/10) of the lyophilized residue provided the title compound (396 mg, 33%): .sup.1H NMR (500 MHz, D.sub.2O) δ ppm 1.83-1.89 (m, 2H), 1.98 (s, 3H), 2.84-2.87 (m, 2H), 3.19-3.21 (m, 2H), 5.01 (s, 2H), 7.03 (d, J=8.8 Hz, 2H), 7.32 (d, J=8.3 Hz, 2H).

Procedure B:

Preparation of Compound C6 sodium salt (4-aza-7-methyl-15-phenyl-11,11-tetramethylene-6,8,14-trioxa-5,9,13-trioxo-1-pentadecanesulfonic acid sodium salt)

[0323] ##STR00133##

[0324] Step 1: 3,3-Tetramethyleneglutaric acid monobenzyl ester (4.26 g; 15.4 mmol, prepared by heating overnight the cyclic anhydride and benzyl alcohol in dioxane at 80° C. in the presence of triethylamine) and silver oxide (2.13 g; 9.22 mmol) were added to a mixture of acetonitrile (40 mL) and water (20 mL). The mixture was heated at 70° C. for 3 h, and then cooled to room temperature. The mixture was filtered through a pad of Celite™. The filtrate was evaporated to provide the crude silver carboxylate (2.19 g, 37%) which was used in the next step without further purification.

[0325] Step 2: A mixture of the silver carboxylate (2.19 g, 5.71 mmol; from step 1) and the carbamating reagent (1.00 g; 2.95 mmol; for preparation, see in Procedure E), in dry toluene (100 mL) was heated at 50° C. overnight. The mixture was filtered through a pad of Celite™ and the filtrate was evaporated to provide a solid residue, which was purified by flash chromatography using hexane/EtOAc (80/20), giving the desired intermediate product (0.915 g, 64%).

[0326] Step 3: To a solution of the intermediate product from step 2 (0.915 g; 1.88 mmol) in dry DMF (5 mL) was added 3-amino-1-propanesulfonic acid sodium salt (300 mg; 1.85 mmol). The mixture was stirred at room temperature overnight. Solvent was removed by evaporation. The residual material was purified by Prep-HPLC to furnish, after lyophilization, the title compound (632 mg, 66%): .sup.1H NMR (CD.sub.3OD, 500 MHz) δ 1.39 (d, J=5.9 Hz, 3H), 1.64-1.59 (m, 8 H), 1.97-1.91 (m, 2H), 2.49 (qAB, J=15.1 Hz, 2H), 2.57 (qAB, J=15.1 Hz, 2H), 2.82-2.79 (m, 2H), 5.10 (s, 2H), 3.26-3.14 (m, 2H), 6.74 (q, J=5.9 Hz, 1H), 7.38-7.29 (m, 5H).

[0327] Other compounds prepared according to this procedure (Procedure B) were purified either by precipitation using methanol and ether (protocol (b)), or by preparative HPLC using acetonitrile/water (10/90 to 90/10) over 40 minutes at 50 mL/min (protocol (a)), or by normal phase flash chromatography (protocol (c)).

Procedure C:

Preparation of Compound C2 sodium salt (4-aza-12-carboxy-6,8-dioxa-5,9-dioxo-7-methyl-11,11-tetramethylene-1-dodecanesulfonic acid sodium salt)

[0328] ##STR00134##

[0329] The corresponding benzylester of the title compound (344 mg; 0.678 mmol) in methanol (5 mL) was hydrogenolyzed in the presence of Pd/C 10% (100 mg) at 40-45 psi for 1 h. The mixture was filtered (Celite™ and the filtrate was evaporated to dryness. The residual material was dissolved in water and the aqueous solution was lyophilized, giving the title compound (242 mg, 86%): .sup.1H NMR (CD.sub.3OD, 500 MHz) δ 1.43 (d, J=5.4 Hz, 3H), 1.66-1.63 (m, 8H), 1.98-1.92 (m, 2H), 2.49 (qAB, J=15.6 Hz, 2H), 2.55 (qAB, J=15.1 Hz, 2H), 2.83-2.80 (m, 2H), 3.24-3.21(m, 2H), 6.77 (q, J=5.4 Hz, 1H), 7.22 (t, J=5.4, N—H).

[0330] Procedure D:

Preparation of Compound C19 sodium salt (4-aza-7-methyl-6,8,-dioxa-5,9,-dioxo-1-decanesulfonic acid sodium salt)

[0331] ##STR00135##

[0332] Step 1: 1-Chloroethylchloroformate (7.8 ml, 72 mmol, 1 eq.) was added to an ice-cold solution of p-nitrophenol (10 g, 72 mmol) in chloroform (100 mL), followed by drop wise addition of pyridine (8.8 ml, 108 mmol, 1.5 eq.) over a period of 20 min. The mixture was stirred in the ice-cold bath for 15 min, and then at room temperature overnight. The reaction mixture was sequentially washed with water, 1 N hydrochloric acid, water, 1 N sodium hydroxide, water, and brine. The organic phase was dried over Na.sub.2SO.sub.4, and concentrated to give yellow oil which, upon standing, crystallized to afford the corresponding chloroethyl carbonate (15.5 g, 88%).

[0333] Step 2: To a solution of the chloroethyl carbonate obtained from step 1 (6.2 g, 25 mmol) in acetic acid (150 mL) was added mercuric acetate (9.6 g, 30 mmol, 1.2 eq.). The mixture was stirred at room temperature overnight. Solvent was evaporated. The residual material was transferred into ether and washed with a saturated aqueous solution of NaHCO.sub.3. The ether layer was dried over MgSO.sub.4 and concentrated to give thick yellow oil. Purification of the oil by flash chromatography (hexane/EtOAc, 95/5) gave the corresponding acetyloxyethyl carbonate (6.3 g, 94%) as colorless oil.

[0334] Step 3: The acetyloxyethyl carbonate obtained from step 2 (1.2 g, 4.3 mmol, 1.1 eq.) was added to a solution of 3-amino-1-propanesulfonic acid sodium salt (0.63 g, 3.9 mmol) in DMF (10 mL). The yellow solution was stirred at room temperature overnight (color disappeared at this point). Solvent was evaporated. The residue was triturated several times with ether and turned to a solid. The solid material was collected by filtration to give the title compound (840 mg, 74%): .sup.1H NMR (500 MHz, CD.sub.3OD) δ 1.42 (d, J=5.4 Hz, 3H), 1.92-1.98 (m, 2H), 2.02 (s, 3H), 2.80-2.83 (m, 2H), 3.20-3.24 (m, 2H), 6.73 (q , J=5.4 Hz, 1H)

[0335] Other compounds prepared according to this procedure (Procedure D) were purified either by extraction from EtOAc/water followed by lyophilization of the aqueous phase, or reverse-phase HPLC purification using acetonitrile/water (10/90 to 90/10) in 40 minutes at 50 mL/min, or trituration/precipitation with ether.

Procedure E:

Preparation of Compound C16 sodium salt (4-aza-7-methyl-6,8,-dioxa-5,9,-dioxo-9-phenyl-1-nonanesulfonic acid sodium salt)

[0336] ##STR00136##

[0337] Step 1: Sodium iodide (14 g, 92 mmol, 3 eq.) was added to a mixture of the chloroethyl carbonate (7.5 g, 31 mmol; for preparation, see in Procedure D), and grinded calcium chloride (10 g, 92 mmol, 3 eq.) in acetonitrile (100 mL). The reaction mixture was stirred at 40 ° C. for 4 days, followed by filtration through a Celite™ pad. The filtrate was concentrated to give a red gummy residue. Purification by flash chromatography using EtOAc/hexane in a gradient mode provided the corresponding iodoethyl carbonate (6 g, 59%) as pale yellow oil.

[0338] Step 2: Silver benzoate (5.5 g, 24 mmol, 2 eq.) was added to a solution of the above-obtained iodoethyl carbonate (4 g, 12 mmol) in toluene (50 mL). The reaction mixture was stirred at 55° C. overnight. The reaction mixture was filtered through a Celite™ pad and washed with toluene. The filtrate was concentrated to give brown oil. Two repeated purifications by flash chromatography using hexane/EtOAc (90/10) provided the corresponding benzoate (0.98 g, 25%) in high purity.

[0339] Step 3: The above-obtained benzoate (0.98 g, 2.9 mmol, 1.1 eq., from step 2) was added to a solution of 3-amino-1-propanesulfonic acid sodium salt (0.43 g, 2.7 mmol) in DMF (10 mL). The yellow solution was stirred at room temperature overnight. Solvent was evaporated and the residue was dissolved in water. The aqueous solution was extracted several times with EtOAc. The aqueous phase was lyophilized to give a residue, which was purified by preparative HPLC (acetonitrile/water; 10/90 to 90/10, in 40 minutes at 50 mL/min), giving the title compound (256 mg): .sup.1H NMR (500 MHz, D.sub.2O) δ 1.48 (d, J=5.4 Hz, 3H), 1.76-1.82 (m, 2H), 2.76-2.79 (m, 2H), 3.08-3.14 (m, 2H), 6.83 (q, J=5.4 Hz, 1H), 7.39-7.42 (m, 2H), 7.55-7.58 (m, 1H), 7.89-7.91 (m, 2H).

Procedure F:

Preparation of Compound C26 sodium salt (3-({[(5-methyl-2-oxo-1,3-dioxol-4-yl)methoxy]carbonyl}amino)-1-propanesulfonic acid sodium salt)

[0340] ##STR00137##

[0341] A mixture of the sodium salt of 3-amino-1-propanesulfonic acid (532 mg; 3.30 mmol) and the carbonate (1.10 g; 3.73 mmol; ref., J. Med. Chem., 1996, 39, 480-486) in dry DMF (10 mL) was stirred at room temperature overnight. Solvent was removed in vacuo. To the residual material was added methanol (10 mL), followed by the addition of ether (75 mL). The solid formed was collected by filtration and dried overnight. Again the solid was dissolved in methanol (10 mL) and precipitated with ether (50 mL). The solid material was purified by preparative HPLC to provide the title compound (260 mg, 25%) as a white lyophilized solid: .sup.1H NMR (CD.sub.2OD, 500 MHz) δ 1.98-1.92 (m, 2H), 2.17 (s, 3H), 2.90-2.79 m, 2H), 3.22 (t, J=6.8 Hz, 2H), 4.86 (s, 2H).

TABLE-US-00007 TABLE 6 Synthesis and characterization of exemplary carbamate prodrugs according to the invention Synthetic Purifying m/z (ES.sup.−) ID procedure protocol* (M − H, or M − Na).sup.† C1 A (a) 330.0 C2 C (d) 394.0 C3 B, C (a) 408.5 C4 C (d) 326.1 C5 B (a) 416.0 C6 B (a) 484.0 C7 B (a) 458.3 C8 C (d) 368.5 C9 C (d) 354.0 C10 B (a) 444.1 C11 C (d) 340.1 C12 B (b) and (a) 430.2 C13 B (b) and (a) 378.0 C14 B (b) and (a) 372.0 C15 D (a) 310.2 C16 E (a) 330.2 C17 D (a) 336.2 C18 D (b) 296.2 C19 D (b) 268.1 C20 D (a) 378.1 C21 D (a) 310.1 C22 D (a) 296.1 C23 D (a) 338.1 C24 D (a) 310.0 C25 E (b) 253.9 C26 F (b) and (a) 294.0 *(a), HPLC; (b), precipitation; (c), flash chromatography; (d), filtration; (e), extraction, .sup.†the compounds were synthesized as acid form, or as sodium salt form.

Example 1-C: Chemical Synthesis of Non-Amino Acid Amide Prodrugs

[0342] Accordingly, the following examples are presented to illustrate how some non-amino acid amide prodrugs according to the invention compounds may be prepared.

Procedure A:

Preparation of Compound B3 sodium salt (3,3-dimethyl-5-oxo-5-[(3-sulfopropyl)amino]pentanoic acid sodium salt)

[0343] ##STR00138##

[0344] A mixture of the 3,3-dimethylglutaric anhydride (1.0 g; 7.0 mmol) and 3-amino-1-propanesulfonic acid sodium salt (0.950 g; 5.86 mmol) in dry DMF (20 mL) was stirred at 50° C. for 2 days. Solvent was evaporated. To the residual material was added methanol (˜10 mL) followed by the addition of ether (˜50 mL) to cause precipitation. The precipitate formed was collected by filtration and then dissolved in water and lyophilized to provide the title compounds (1.33 g, 75%) as a powder: .sup.1H NMR (D.sub.2O, 500 MHz) δ 0.94 (s, 6H), 1.82-1.77 (m, 2H), 2.14 (s, 3H), 2.23 (s, 3H), 2.79-2.76 (m, 2H), 3.16 (t, J=6.8 Hz, 2H).

[0345] Other compounds prepared in the above procedure (Procedure A, see Table 7) were purified either by methanol-ether precipitation (Purification protocol (b)), or using preparative HPLC (Purification protocol (a)), or by normal-phase flash-chromatography (Purification protocol (c)). Reaction time for Compounds B1 and B2 was 4 days; and for all other compounds, 2 days.

Procedure B:

Preparation of Compound B7 (3-[3-(2-Hydroxy-((S)-valyl ester)-4,6-dimethyl-phenyl)-3-methyl-butyrylamino]-1-propanesulfonic acid)

[0346] ##STR00139##

[0347] Step 1: EDC (N-(3-dimethylaminopropyl)-W-ethylcarbodiimide) (6.4 g, 33 mmol, 3 eq.) was added, at 0° C., to a 150-mL dry dichloromethane solution containing Boc-Val-OH (4.9 g, 22 mmol, 2 eq.), the silylated phenol (3.6 g, 11 mmol; ref., J. Med. Chem., 2000, 43, 475-487), and DMAP (4-(dimethylamino)pyridine, 5.5 g, 45 mmol, 4 eq.). The reaction mixture was stirred at room temperature overnight, then diluted with dichloromethane, and washed with a saturated aqueous solution of NaHCO.sub.3, 1N HCl, and brine subsequently. The organic layer was dried and concentrated to a colorless oil residue. Purification of the residual material (flash chromatography; using hexane/EtOAc, 95/5) gave the corresponding intermediate (5.7 g, 99%) as a colorless oil.

[0348] Step 2: The intermediate from step 1 (5.7 g, 11 mmol) was stirred in a mixture of THF-water-acetic acid (20 mL/20 mL/60 mL) at room temperature for 3 h; then the solvent was removed and the residue dried in vacuo. The residual material (the free alcohol) obtained was used in the next step without further purification

[0349] Step 3: A solution of the alcohol (11 mmol, from step 2) in dichloromethane (125 mL) was slowly added to a suspension of PCC (pyridinium chlorochromate, 5.0 g, 23 mmol, 2.1 eq.) in dry dichloromethane (125 mL). The reaction mixture was stirred at room temperature overnight. Solvent was evaporated and the residue was dissolved in a minimum amount of dichloromethane. The resulting dichloromethane solution was passed through a silica gel column using Hexane/EtOAc (50/50). Evaporation of the solvent gave the corresponding aldehyde as yellow oil which was directly used in the next step without further purification.

[0350] Step 4: A solution of 80% sodium chlorite (2.5 g, 28 mmol, 2.5 eq.) in water (10 mL) was added slowly to a solution of the aldehyde (11 mmol, form step 3) and sodium dihydrogen phosphate (818 mg, 6.8 mmol, 0.6 eq.) in acetonitrile (20 mL) and water (20 mL) at 0° C. The mixture was stirred 1 h at 0° C. then at room temperature for 1 h. Sodium sulfite (1.5 g, 1 eq.) was added to decompose peroxides, and the pH was adjusted to 2 with 1N HCl solution. Reaction mixture was extracted twice with EtOAc. The organic layers were washed with brine, dried, and concentrated. Purification of the residual material (flash chromatography; CH.sub.2Cl.sub.2/CH.sub.3OH, 100/0 to 95/5) gave the corresponding carboxylic acid (3.4 g, 73%) as a foam.

[0351] Step 5: EDC (908 mg, 4.75 mmol, 2 eq.) was added to a mixture of the carboxylic acid (1 g, 2 mmol; from step 4), 3-amino-1-propanesulfonic acid sodium salt (380 mg, 2.34 mmol) and a catalytic amount of DMAP in DMF (10 mL). The reaction mixture was stirred at room temperature overnight. Solvent was removed and the residue was dried in vacuo to provide the corresponding derivative of 3-amino-1-propanesulfonic acid which was used in the next step without further purification.

[0352] Step 6: Trifluoroacetic acid (5 mL) was added to a solution of the 3-amino-1-propanesulfonic acid derivative (2.4 mmol, from step 5) in dichloromethane (5 mL) at room temperature. The reaction mixture was stirred for 2 h, followed by evaporation of the solvent. The resulted residue was purified (preparative HPLC; acetonitrile/water, 5/95 to 70/30 in the presence of 0.01% TFA) to yield, after lyophilization, the title compound (0.3 g, 29%) as a white solid: .sup.1H NMR (500 MHz, D.sub.2O) δ1.04 (d, J=7 Hz, 3H), 1.07 (d, J=7 Hz, 3H), 1.39 (s, 3H), 1.45 (s, 3H), 1.55-1.58 (m, 2H), 2.11 (s, 3H), 2.43 (s, 3H), 2.45-2.58 (m, 5H), 2.98-3.02 (m, 2H), 4.26 (d, J=4 Hz, 1 H), 6.54 (d, J=1.5 Hz, 1 H), 6.93 (d, J=1.5 Hz, 1H).

Procedure C:

Preparation of Compound B14: 3-{[(3α,5β,7α,12α)-3,7,12-trihydroxy-24-oxo-cholan-24-yl]amino}-1-propanesulfonic acid

[0353] ##STR00140##

[0354] To a mixture of (+)-cholic acid (5.0 g, 12.2 mmol), 3-amino-1-propanesulfonic acid sodium salt (1.85 g, 11.5 mmol), 4-dimethylaminopyridine (72 mg, 0.6 mmol) in DMF (30 mL) was added N-(3-dimethylaminopropyl)-N′-ethylcarbodimide hydrochloride (EDC, 4.68 g, 24.4 mmol). The reaction mixture was stirred at room temperature overnight. The cloudy mixture was filtered through sintered glass before the solvent was evaporated to dryness under reduced pressure. The viscous residue was dissolved in water (30 mL). The solution was treated with Dowex Marathon C™ ion exchange resin (strongly acidic, 30 g, pre-washed). The suspension was stirred for 15 minutes before the resin was removed by filtration. The filtrate was concentrated to dryness under reduced pressure and dried in vacuo. The residue was triturated with diethyl ether (1000 mL). The solid product was recovered by filtration and dried in vacuo. The crude product was purified by flash chromatography (Biotage™ SP1: 20-40% EtOH in CH.sub.2Cl.sub.2) and the corresponding fractions were collected and lyophilized, affording the title compound (178 mg, 3%); .sup.1H NMR (D.sub.2O, 500 MHz) δ ppm 0.73 (s, 3H), 0.93 (s, 3H), 1.02 (m, 4H), 1.31 (m, 7H), 1.52 (d, 1H, J=14.5 Hz), 1.65 (m, 6H), 1.79 (m, 3H), 1.94 (m, 3H), 2.04 (m, 3H), 2.23 (m, 1 H), 2.31 (m, 1 H), 2.92 (m, 2H), 3.31 (m, 2H), 3.52 (m, 1H), 3.92 (s, 1H), 4.08 (s, 1H); .sup.13C NMR (D.sub.2O, 125 MHz) 8 ppm 12.31, 16.82, 22.33, 23.12, 24.30, 26.48, 27.47, 27.95, 29.37, 31.87, 32.71, 34.06, 34.54, 35.09, 35.33, 38.15, 38.49, 39.50, 41.29, 41.64, 46.27, 46.28, 48.73, 68.33, 71.69, 73.14, 177.44; m/z (ES.sup.+) 530; [α].sub.D=+25.7° (c=0.005, water).

TABLE-US-00008 TABLE 7 Synthesis and characterization of exemplary non-amino acid amide prodrugs according to the invention Synthetic Purifying m/z (ES.sup.−) ID procedure protocol* (M − H, or M − Na).sup.† B1 A (a) 320.4 B2 A (a) 306.5 B3 A (b) 280.2 B4 A (c) 280.3 B5 A (b) 238.0 B6 A (b) 525.0 B7 B (a) 441.3 B9 B (a) 491.4 B10 B (a) 457.3 B11 B** (a) 514.2 B13 B** (a) 548.1 *(a), HPLC; (b), precipitation; (c), flash chromatography; (d), filtration; (e), extraction; **Procedure B, replacing 3-APS by N-glycyl-3-APS; .sup.†the compounds were synthesized as acid form, or as sodium salt form.

Example 1-D: Chemical Synthesis of Carbohydrate-Derived Prodrugs

[0355] Accordingly, the following examples are presented to illustrate how some carbohydrate-derived prodrugs according to the invention compounds may be prepared.

Synthesis of Compound S1 Sodium Salt

[0356] ##STR00141##

[0357] A suspension of glucose (2 g, 11.1 mmol) and the sodium salt of 3APS (2.24 g, 11.1 mmol) in MeOH (10 mL) was refluxed for 30 min before being cooled down to room temperature. After 24h of stirring at room temperature, the solid was filtrated and washed twice with MeOH (2×10 mL). The resulting solid was dried overnight under high vacuum and afford the sodium salt of Compound S1 (3.1 g, 9.6 mmol, 86%) as a white solid. .sup.1H NMR (D.sub.2O) (500 MHz) δ ppm 4.55 (d, J=4.4 Hz, 0.33H, α-anomer), 3.87 (d, J=9.3 Hz, 0.66H, α—anomer), 3.74 (dd, J=12.2, 1.5 Hz, 0.66H), 3.70 (dd, J=12.7, 2.4 Hz, 0.33H), 3.61 (dd, J=12.2, 4.9 Hz, 0.33H), 3.56 (dd, J=12.2, 5.4 Hz, 0.66H), 3.53-3.49 (m, 1H), 3.33 (t, J=9.3 Hz, 0.66H), 3.25-3.20 (m, 1 H), 3.05 (t, J=8.8 Hz, 0.33H), 2.83 (m, 2.66H), 2.68 (m, 1 H), 2.57 (m, 0.33H), 1.78 (m, 2H). m/z (ES″) 300.0 (M−H).

Synthesis of Compound S2

[0358] ##STR00142##

[0359] Methyl 6-bromo-6-deoxy-α-D-glucopyranoside was Prepared According to Tetrahedron 1991, 28(47), 5185-5192

[0360] Step 1: A stirred suspension of bromide (1 g, 3.89 mmol) and sodium azide (278 mg, 4.28 mmol) in DMF (10 ml) was stirred at 90° C. for 5 days. After being cooled down to room temperature, the solution was evaporated under vacuum and the residue was purify by chromatography on silica gel (CHCl.sub.3/MeOH 95/5 to 70/30 linear gradient) to afford the desired azido (776 mg, 3.54 mmol , 91%) as a white solid.

[0361] Step 2: A solution of the previously prepared azido derivative (776 mg, 3.54 mmol) in MeOH (10 ml) was degazed with N.sub.2 for 10 min before a suspension of 10% Pd/C (50 mg) in CHCl.sub.3 was added. After being stirred 2 h under H.sub.2 pressure (40 PSI), the solution was filtrated over a pad of Celite™ (MeOH) and evaporated under vacuum and afforded the desired amine (628 mg, 3.25 mmol, 92% crude) as a yellow oil. This compound was used in the next step without further purification.

[0362] Step 3: A solution of sultone (285 μl, 3.25 mmol) in CH.sub.3CN (5 ml) was added drop wise (over 30 min) to a refluxing solution of the previously prepared amine (628 mg, 3.25 mmol) in a 2/1 mixture CH.sub.3CN/EtOH (10 ml). The resulting solution was heated under reflux for 15 h before being cooled down to room temperature and evaporated under vacuum. The residue was purified by chromatography on silica gel (i-PrOH/H.sub.2O (0.5% NH.sub.4OH) 98/2 to 80/20 linear gradient). After Evaporation, the compound was passed through a C-8 pad (H.sub.2O) and lyophilized and afforded Compound S2 (450 mg, 1.43 mmol, 44% over two steps) as a white solid. NMR .sup.1H (D.sub.2O) (500 MHz): 2.06(m, 2H), 2.92(t, J=7.0 Hz, 2H), 3.13 (m, 3H), 3.21 (t, J=9.5 Hz, 1H), 3.34 (s, 3H), 3.36 (dd, 12.5, 3 Hz, 1H), 3.48 (dd, J=9.5, 3.5 Hz, 1H), 3.56 (t, J=9.0 Hz, 1H), 3.77 (dt, J=9.0, 2.5 Hz, 1 H), 4.74 (d, J=3.5 Hz, 1 H). ES (MS) 314.1 (M−H). [α].sub.D=+86.3 (c 1.0, H.sub.2O)

Procedure A: General Procedure for the Deprotection of 1,2,3,4- or 2,3,4,6-tetraacetate Glucose Derivative

[0363] To a stirred solution of the protected glucose derivative was added enough of a solution of NaOMe (sodium methoxide, 0.5M in MeOH) in order to obtain a basic pH (8-9, pH paper). The resulting solution was stirred at room temperature until completion (the reactions were generally followed by MS) before addition of twice the initial volume of CH.sub.3CN. The resulting solid was then filtrated and washed several time with CH.sub.3CN, acetone and diethyl ether. The resulting solid was then passed trough a C8 column (0.5% NH.sub.4OH in H.sub.2O) and lyophilized to afford the desired compound.

Synthesis of Compounds S3 and S4

[0364] ##STR00143##

[0365] Step 1: A suspension of the sodium salt of 3-amino-1-propanesulfonic acid (398 mg, 2.47 mmol) and glucopyranuronic anhydride (398 mg, 2.47 mmol) in DMF (15 mL) was stirred 3 days at room temperature before evaporation of the solvent under vacuum. The residue was purified by chromatography on silica gel (CHCl.sub.3/MeOH 100/0 to 70/30 linear) to afford compound S3 (719 mg, 1.49 mmol, 60%) as a white foam. .sup.1H NMR (CD.sub.3OD, 500 MHz) δ ppm 1.96(m, 2H), 1.98(s, 3H), 2.01(s, 3H), 2.02(s, 3H), 2.09(s, 3H), 2.83(m, 2H), 3.31(m, 2H), 4.19(d, J=9.5 Hz, 1H, H.sub.5), 5.12(t, J=8 Hz, 1H, H.sub.2), 5.19(t, J=10 Hz, 1H, H.sub.4), 5.38(t, J=9 Hz, 1H, H.sub.3), 5.87(d, J=8.5 Hz, 1H, H.sub.1). m/z (ES) 482.4 (M−H); =+6.2 (c 0.93, MeOH).

[0366] Step 2: Compound S3 (190 mg, 0.54 mmol) was treated according to Procedure A to afford Compound S4 (150 mg, 0.48 mmol, 88%) as a white solid. .sup.1H NMR (D.sub.2O, 500 MHz) δ ppm 1.92 (m, 2H), 2.90 (m, 2H), 3.27 (t, J=8.5 Hz, 0.5H), 3.32 (m, 2H), 3.47-3.50 (m, 1.5H), 3.56 (dd, J=9.5, 4.0 Hz, 0.5H), 3.69 (t, J=9.0 Hz, 0.5H), 3.86 (d, J=7.0 Hz, 0.5H), 4.16 (d, J=10.0 Hz, 0.5H), 4..6-4.7 (0.5H, under water peak), 5.25 (d, J=3.5 Hz, 0.5H); m/z (ES.sup.−) 314.4 (M−H).

Synthesis of Compound S5 Sodium Salt and Compound S6 Ammonium Salt

[0367] ##STR00144##

2,3,4,6-Tetra-O-acetyl-D-glucose was prepared according to J. Am. Chem. Soc. 1993, 115, 2260-2267.

[0368] Step 1: p-nitrophenolchloroformate (638 mg, 3.16 mmol) was added to a stirred solution of tetraacetylglucose (1 g, 2.87 mmol) and Et.sub.3N (800 μl, 5.74 mmol) in CH.sub.2Cl.sub.2 (20 ml) and the reaction was stirred overnight at room temperature. A 1N aqueous solution of hydrochloric acid (10 ml) was added and the layers were separated. The aqueous layer was extracted twice with CH.sub.2Cl.sub.2 (20 ml) and the combined organic layer were washed subsequently with a saturated solution of sodium carbonate (10 ml) and a saturated solution of sodium chloride. The organic layer was then dry over MgSO.sub.4, filtrated and the solvent was evaporated under vacuum. The residue was purified by chromatography on silica gel (Hex/EtOAc 90/10 to 5050, linear gradient) to afford the desired carbonate (1.108 g, 2.16 mmol, 75%) as colorless solid.

[0369] Step 2: Pyridine (524 ml, 6.48 mmol) was added to a suspension of the carbonate previously prepared (1.108 g, 2.16 mmol) and the sodium salt of 3APS (522 mg, 2.16 mmol). After 3 days of stirring at room temperature, the solvent was evaporated under vacuum and the residue was purified by chromatography on silica gel (CHCl.sub.3/MeOH 100/0 to 80/20, linear gradient) to afford Compound S5-Sodium salt (1.066 g, 2.07 mmol, 96%) as a white solid. .sup.1H NMR (D.sub.2O, 500 MHz) 5 ppm 1.97 (s, 3H), 2.00 (s, 3H), 2.01 (s, 3H), 2.1 (m, 2H, hide), 2.05 (s, 3H), 2.83 (m, 2H), 3.25 (m, 2H), 3.98 (br d, J=8.0 Hz, 0.4H, H.sub.5b), 4.09 (t, J=10.5 Hz, 1H, H.sub.6), 4.17 (br d, J=10.2 Hz, 0.6H, H.sub.5a), 4.26-4.30 (m, 1H, H.sub.6), 4.99-5.12 (m, 2H, H.sub.2a, H.sub.2b, H.sub.4b, H.sub.4a), 5.32 (t, J=9.5 Hz, 0.40H, H.sub.3b), 5.50 (t, J=9.9, 0.6H, H.sub.3a), 5.69 (d, J=8.4 Hz, 0.3H, H.sub.1b), 6.17 (d, J=3.5 Hz, 0.6H, H.sub.1a). m/z (MS) 512.5 (M−H).

[0370] Step 3: Compound S5 sodium salt (500 mg, 0.97 mmol) was treated according to Procedure A to afford Compound S6-ammonium salt (220 mg, 0.64 mmol, 66%) as a white solid. .sup.1H NMR (D.sub.2O (500 MHz) δ ppm 1.80 (m, 2H), 2.80 (m, 2H), 3.15 (m, 2H), 3.30-3.37 (m, 1.5H), 3.41-3.43 (m, 1H), 3.68-3.53 (m, 3H), 3.75 (d, J=12.2 Hz, 0.5H), 5.26 (d, J=8.2 Hz, 0.5H, H.sub.1b), 5.82 (d, J=3.05 H2, 0.5H, H.sub.1a). m/z (ES) 344.4 (M−H).

Synthesis of the Sodium Salt of Compound S7

[0371] ##STR00145##

2-(p-nitrophenyl carbamate)-ethyl-2,3,4,6-tetra-O-acetyl-,6-D-glucopyranoside was prepared according to Org. Lett. 2000, 2(8), 1093-1096.

[0372] Step 1: 3APS-sodium salt (223 mg, 1.38 mmol) was added to a stirring solution of p-nitrophenyl carbamate (643 mg, 1.16 mmol) in DMF (7 mL). After 24 h of stirring at room temperature, the solvent was evaporated under vacuum and the residue was purified by chromatography on silica gel (CHCl.sub.3/MeOH 100/0 to 70/30, linear gradient) and afforded the desired sulfonate (596 mg, 1.07 mmol, 92%) as a white solid.

[0373] Step 2: The 2,3,4,6-tetra-O-acetyl-D-glucose previously prepared (596 mg, 1.07 mmol) was treated according to Procedure A to afford Compound S7-sodium salt (260 mg, 0.67 mmol, 63%) as a white solid. .sup.1H NMR (D.sub.2O, 500 MHz) δ ppm 1.91 (m, 2H, H11), 2.93 (t, J=7.5 Hz, 2H, H12), 2.24 (t, J=6.0 Hz, H10), 3.28 (t, J=9.0 Hz, 1H, H2), 3.34 (m, 2H, H8), 3.38 (t, J=9.5 Hz, 1H, H4), 3.45 (m1, 1H, H6a), 3.49 (dd, J=9, 9 Hz, 1H, H3), 3.7-3.77 (m, 2H, H6a, H7a), 3.91 (apparent d, J=11.5 Hz, H5, H7b), 4.46 (d, J=8.0 Hz, H1). m/z (ES) 386.9 (M−H).

Synthesis of the Sodium Salt of Compounds S8 and S9

[0374] ##STR00146##

N-(9-Fluorenylmethoxycarbonyl)-3-O-(2,3,4,6-tetra-β-acetyl-β-D-glucopyranosyl)-L-serine Pentafluorophenyl ester was prepared according to J. Med. Chem. 1995, 38, 161-169.

[0375] Step 1: 3APS-sosium salt (258 mg, 1.60 mmol) was added to a stirring solution of pentaflurophenyl ester (1200 mg, 1.45 mmol) in DMF (15 mL). After 24 h of stirring at room temperature, the solvent was evaporated under vacuum and the residue was purified by chromatography on silica gel (CHCl.sub.3/MeOH 100/0 to 80/20, linear gradient) to afford the desired sulfonate (1070 mg, 1.37 mmol, 94%) as a white solid.

[0376] Step 2: Piperidine (2.7 mL, 27 mmol) was added to a stirred solution of previously prepared Fmoc serine derivative (1070 mg, 1.37 mmol) in DMF (15 mL). After stirred for 1 h, solvent was evaporated under reduced pressure. The residue was purified by chromatography on silica gel (CHCl.sub.3/MeOH 100/0 to 75/25, linear gradient) to afford the desired amine Compound S8-sodium salt (350 mg, 0.63 mmol, 46%) as a white solid.

[0377] Step 3: The 2,3,4,6-tetra-O-acetyl-D-glucose previously prepared (350 mg, 0.63 mmol) was treated according to Procedure A to afford Compound S9-sodium salt (210 mg, 0.54 mmol, 86%) as a white solid. .sup.1H NMR (D.sub.2O, 500 MHz) 1.95 (m, 2H, H11), 2.94 (t, J=8.0 Hz, 2H, H12), 3.35 (dd, J=7.5, 9.0 Hz, 1H, H2), 3.36-3.41 (m, 3H, H4, H10), 3.42-3.50 (m, 2H, H3, H5), 3.73 (dd, J=6.0, 1 H, 12.0 Hz, H6a), 3.92 (br d, J=12.0 Hz, 1 H, H6b), 3.96 (dd, J=4.5, 1H, 11.5 Hz, H8), 4.05 (t, J=4.5 Hz, 1H, H7a), 4.22 (dd, J=4.5, 11.5 Hz, 1H, H7), 4.47 (d, J=7.5 Hz, 1H, H1). m/z (ES) 387.25 (M−H).

Synthesis of the Sodium Salt of Compounds S14 and S15

[0378] ##STR00147##

[0379] 1,2,3,4-tetra-O-acetyl-α-D-glucopyranoside was prepared according to Org. Lett. 2006, 8, 2393-2396 and J. Am Chem. Soc. 2000, 122, 12151-12157.

[0380] Step 1: p-Nitrophenolchloroformate (3 g, 14.8 mmol) was added to a stirred solution of 1,2,3,4-tetra-O-acetyl-α-D-glucopyranoside (4.7 g, 13.4 mmol) and triethylamine (3.7 ml, 26.8 mmol) in dichloromethane (100 mL). The reaction mixture was stirred overnight at room temperature. A 1N aqueous solution of hydrochloric acid (30 mL) was added and the layers were separated. The aqueous layer was extracted twice with dichloromethane (100 mL) and the combined organic layers were washed subsequently with a saturated solution of sodium carbonate (50 mL) and then with a saturated solution of sodium chloride. The organic layer was dried over magnesium sulfate, filtered and the solvent was evaporated under vacuum. The residue was purified by chromatography on silica gel (hexanes/ethyl acetate 90/10 to 50/50, linear gradient), affording the corresponding carbonate (4.7 g, 68%) as a colorless solid.

[0381] Step2: The sodium salt of 3APS (2.22 g, 13.8 mmol) was added to a solution of the carbonate previously prepared (4.7 g, 9.16 mmol) in N,N-dimethylformamide (50 mL). After 3 days of stirring at room temperature, the solvent was evaporated under vacuum and the residue was purified by chromatography on silica gel (dichloromethane/methanol 100/0 to 70/30, linear gradient) and afforded Compound S15-sodium salt (1.95 g, 41%) as a white solid together with its 1-deactetylated derivative (1.21 g, 36%) as a white solid: .sup.1H NMR (D.sub.2O, 500 MHz) δ ppm 1.91-2.02 (m, 11H), 2.07 (s, 2H), 2.17 (s, 1 H), 2.86 (m, 2H, H1), 3.24 (t, J=8.0 Hz, 2H, H3), 3.99 (m, 0.7H, H6B), 4.10-4.20 (m, 2.3H, H5 and H6a), 5.02 (m, 1H, H9), 5.08 (t, J=10.0 Hz, 0.7H, H7B), 5.13 (t, J=9.5 Hz, 0.3H, H7a), 5.34 (t, J=9.5 Hz, 0.7H, H8β), 5.44 (t, J=9.5 Hz, 0.3H, H8α), 5.81 (d, J=8.0 Hz, 0.7H, H10β), 6.28 (d, J=3.5 Hz, 0.3H, H10α); m/z (ES) 512.0 (M−H).

[0382] Step3: Compound S15-sodium salt (1.37 g, 2.67 mmol)) was treated according to Procedure A to afford Compound S14-sodium salt (520 mg, 1.51 mmol, 56%) as a white solid: .sup.1H NMR(D.sub.2O, 500 MHz) δ ppm 1.80 (m, 2H, H2); 2.81 (m, 2H, H1), 3.12 (m, 2.55H, H3 and H9β); 3.31 (m, 1H, H7α and H7β); 3.36 (m, 0.55H, H8β); 3.41 (dd, J=10.0, 4.0 Hz, 0.45H, H9α); 3.48 (m, 0.55H, H6β); 3.56 (t, J=9.0 Hz, 0.45H, H8α); 3.84 (brd, J=10.0 Hz, 0.45H, H6α), 4.10 (m, 1H, H5a), 4.23 (apparent t, J=12.5 Hz, 1H, H5b), 4.51 (d, J=8.0 Hz, 0.55H, H10β); 5.08 (d, J=4.0 Hz, 0.45H, H10α); m/z (ES) 344.0 (M−H).

Synthesis of the Sodium Salt of Compounds S16 and S17

[0383] ##STR00148##

2,3,4,6-Tetra-O-acetyl-D-glucose-1-propanol was prepared according to J. Am. Chem. Soc. 1940, 62, 917-920.

[0384] Step 1: p-Nitrophenolchloroformate (2.3 g, 11.4 mmol) was added to a stirred solution of 3-hydroxy-1-propyl 2,3,4,6-tetra-O-acetyl-β-D-glucopyranoside (3.1 g, 7.64 mmol) and triethylamine (2.12 mL, 11.44 mmol) in dichloromethane (60 mL) and the reaction mixture was stirred overnight at room temperature. Aqueous hydrochloric add (1N, 15 mL) was added and the layers were separated. The aqueous layer was extracted 2 times with dichloromethane (40 mL) and the combined organic layer were washed subsequently with a saturated solution of sodium carbonate (15 mL) and then with a saturated solution of sodium chloride. The organic layer was then dried over magnesium sulfate, filtrated and the solvent was evaporated under vacuum. The residue was purified by chromatography on silica gel (hexanes/ethyl acetate 90/10 to 50/50, linear gradient) to afford the corresponding carbonate (3.1 g, 71%) as colorless solid.

[0385] Step2: The sodium salt of 3-APS (655 mg, 4.07 mmol) was added to a solution of the carbonate previously prepared (1.55 g, 2.71 mmol) in N,N-dimethylformamide (50 mL). After 3 days of stirring at room temperature, the solvent was evaporated under vacuum and the residue was purified by chromatography on silica gel (dichloromethane/methanol 95/5 to 70/30, linear gradient) to afford a mixture of Compound S17 and p-nitrophenol (1.33 g) as a white solid, which was used in next step without further purification.

[0386] Step3: The crude Compound S17 (1.33 g) was treated according to Procedure A to afford Compound S16-sodium salt (850 mg, 49% over two steps) as a white solid: .sup.1H NMR (D.sub.2O, 500 MHz) δ ppm 1.84-1.91 (m, 4H, H6+H2), 2.88 (m, 2H, H1), 3.18 (m, 2H, H3), 3.21 (t, J=8.5 Hz, 1H, H9), 3.33 (t, J=9.3 Hz, 1H, H11), 3.39 (m, 1H, H12), 3.44 (t, J=9.3 Hz, 1H, H10), 3.67 (dd, J=12.3, 5.8 Hz, 1H, H13a), 3.71 (m, 1H, H7a), 3.85 (dd, J=12.3, 2.0 Hz, 1H, H13b), 3.94 (m, 1 H, H7b), 4.10 (m, 2H, H5), 4.39 (d, J=8.0 Hz, 1 H, H8); m/z (ES) 402.1 (M−H).

Example 1-E: Chemical Synthesis of Imine-Derived Prodrugs

[0387] Accordingly, the following examples are presented to illustrate how some imine-derived prodrugs according to the invention compounds may be prepared.

Synthesis of Compound M7 Sodium Salt

[0388] ##STR00149##

[0389] Sodium 3-amino-1-propanesulfonate (0.64 g, 4.0 mmol) was added to a solution of 4′-chloro-5-fluoro-2-hydroxy-benzophenone (0.50 g, 2.0 mmol) in methanol (50 mL). The reaction mixture was stirred under reflux for 4 h then concentrated under reduced pressure. The residual material was purified by flash chromatography (silica gel, chloroform: methanol 90:10 then 80:20) to afford the title compound (0.51 g, 64%): .sup.1H NMR (CDCl.sub.3, 500 MHz) δ 1.89 (m, 2H), 2.5 (t, J=7.0 Hz, 2H), 3.36 (t, J=7.0 Hz, 2H), 6.95 (m, 1 H), 6.95 (m, 1 H), 7.22 (m, 1H), 7.38 (d, J=8.0 Hz, 2H), 7.66 (d, J=8.0 Hz, 2H), 15.27 (s, 1H). ES-MS (370 M-1).

Synthesis of Compound M7-sulfonamide

[0390] ##STR00150##

[0391] Step 1: To a stirred solution of sodium azide (3.5 g, 50 mmol) in water (25 mL) was added a solution of 1,3-propane sultone (6.1 g, 50 mmol) in acetone (25 mL). The reaction mixture was stirred at room temperature for 24 h then concentrated to dryness. The resulting solid was suspended in diethyl ether (100 mL) and stirred at reflux for 1 h. The suspension was cooled to room temperature and the solid was collected by filtration, washed with acetone and diethyl ether, and dried under vacuum, affording of 3-azido-1-propanesulfonic acid (7.6 g, 80%).

[0392] Step 2: PCl.sub.5 (2.61 g, 12.53 mmol) was added to a suspension of 3-azido-1-propanesulfonic acid (2.07 g, 12.53 mmol) in toluene. The reaction mixture was stirred under reflux for 3 h. After cooling to room temperature, the solvent was evaporated, and the resulting material was used in the next step without further purification.

[0393] Step 3: Ammonium hydroxide (28%) (10 mL) was added to a solution of 3-azido-1-propanesulfonyl chloride (=2.29 g, 12.53 mmol; obtained in step 2) in ethanol (10 mL). The reaction mixture was stirred at room temperature for 3 h then concentrated. The residual material was passed through a short silica gel column using hexanes:ethyl acetate as eluent to isolate 3-azido-1-propanesulfonamide (1.5 g, 86%).

[0394] Step 4: 3-Azido-1-propanesulfonamide (1.5 g, 10.86 mmol; obtained from step 3) was dissolved in water/ethanol (10 mL/10 mL), followed by addition of 10% Pd/C (0.2 g). The resulting suspension was stirred under atmospheric pressure of H.sub.2 for 5 h. The insoluble material was removed by filtration; and the filtrate was concentrated. The residual material was suspended in hydrogen. The suspension was filtered and the resulting solid was washed with ethanol and diethyl ether, dried under high vacuum, affording 3-amino-1-propanesulfonamide (1.2g, 80%).

[0395] Step 5: 3-Amino-1-propanesulfonamide (0.55 g, 4 mmol; from step 4) was added to a solution of 4′-chloro-5-fluoro-2-hydroxy-benzophenone (1 g, 4 mmol) in methanol (50 mL). The reaction mixture was stirred under reflux for 5 h then concentrated under reduced pressure. The residual material was purified by column chromatography (silica gel, dichloromethane:methanol 90:10 then 80:20). The corresponding solid (after removal of solvent) was recrystallized in diethyl ether to afford 3-{[(1E)-(4-chlorophenyl)(5-fluoro-2-hydroxyphenyl)methylene]amino}propane-1-sulfonamide (0.75 g, 51%). .sup.1H NMR (CDCl.sub.3, 500 MHz) δ 2.21 (m, 2H), 3.24 (t, J=7.0 Hz, 2H), 3.47 (t, J=7.0 H, 2H), 4.63 (bs, 2H), 6.93 (m, 1H), 6.95 (m, 1H), 7.04 (m, 1H), 7.13 (d, J=8.2 Hz, 2H), 7.54 (d, J=8.2 Hz, 2H), 14.71 (s, 1H). ES-MS (369 M−1).

Example 2: In Vitro Stability and Metabolism

[0396] In vitro stability of exemplary prodrugs of the invention was tested in water, in an acidic aqueous solution (pH: 1.5), in PBS, in human and mouse microsomes, and in human and mouse whole blood.

A. Stability in Water, at pH: 1.5 and PBS

[0397] Stability of exemplary compounds was determined in water, aqueous acidic solution (pH 1.5, HCl) and PBS (phosphate buffered saline) solution using ESI-MS (electrospray ionization mass spectrometry) as the detecting instruments. In general a 2 μg/mL pro-drug solution containing 1 μg/ml IS (internal standard) was prepared and incubated for 60 min. For water stability the incubation was performed at room temperature and for stability in acidic solution and in buffer. The incubation temperature was 37° C. Samples were analyzed for prodrug content at time points 0 and 60 min. using MS. The % changes in peak area ratio after 60 minutes for each test compound tested are calculated using the average values from six replicate runs. The compounds tested included Compounds A1 to A19, Compounds B5 and B6 and Compounds C1 to C26. Except for C26 which was found unstable at pH 1.5 and in PBS, all other compounds were judged to be stable under all conditions tested with less than about 15%-20% concentration change after 60 minutes.

B. Metabolism in Mouse and Human Microsomes

[0398] Microsomal stability of Compounds A1, A2, A3, C17, C18 and C19 was determined in duplicate, in presence of pooled mouse or human liver microsomes for up to 60 minutes at 37° C. Briefly, microsomes were diluted to achieve a concentration of 1.0 mg/mL in PBS buffer (pH 7.4) containing 3 mM MgCl.sub.2 and 1 mM EDTA. Compounds (10 μM) and microsomes were pre-incubated for a period of 5 minutes before the enzymatic reaction was started by addition of co-factors (1 mM NADPH- and 2 mM UDPGA in PBS buffer). After a 1-hour incubation period, the reaction was stopped by the addition of ice cold acetonitrile. For time 0 samples, the reaction was stopped with acetonitrile before the addition of the co-factors. Analysis of extracted samples was achieved using HPLC with MS detection. Several types of HPLC columns and mobile phases were used depending of the polarity of the compound. The compound stability was determined by the % of compound remaining at 60 minutes (peak response of compound at 60 minutes/peak response at 0 minutes×100). Four of the compounds tested (three amino acid prodrugs A1, A2, A3, and the carbamate prodrug C19) were found stable, with over 90% of the compounds remaining after 60 minutes in presence of mouse or human microsomes (data not shown). Compound C17 was found less stable with between 20 and 35% of the prodrug remaining after 60 minutes in presence of mouse or human microsomes, while carbamate C18 showed moderate stability with between 75 and 80% of the prodrug remaining under the same conditions.

C. Mouse and Human Whole Blood Stability

[0399] Test compounds were incubated for a total of 240 minutes at 37° C. in whole mouse and whole human blood. The compounds were added at time-point 0 and sample aliquots were withdrawn at each time point (usually 0, 60 and 240 minutes). The samples were extracted using protein precipitation. Analysis of extracted samples was achieved using HPLC with MS detection. Several types of HPLC columns and mobile phase were used depending of the polarity of the compound. The compound stability was determined by the % of compound remaining at 240 minutes (peak response of compound at 240 minutes/peak response at 0 minutes×100). Results are summarized in Table 8.

TABLE-US-00009 TABLE 8 Stability in mouse and human whole blood Blood stability (% of compound remaining after 240 min.) ID Human Blood Mouse Blood A1 ND + A2 ND ++ A3 ND ++ A4 + +++ A5 + + A6 ++ + A7 +++ +++ A8 + ++ A9 +++ +++ A10 ++ ++ A11 +++ +++ A12 +++ +++ A13 +++ +++ A14 +++ +++ A15 ++ + A16 +++ ++ A18 + + A19 + + B3 +++ ++ B4 +++ +++ B5 +++ +++ B6 +++ +++ C1 + + C4 +++ ++ C5 + + C7 +++ + C8 +++ +++ C9 ++ ++ C10 + + C11 +++ +++ C12 ++ + C13 + + C14 +++ ++ C15 ++ + C16 ++ + C17 ND + C18 ND + C19 ND + C20 ++ + C21 ++ + C22 ++ + C23 ++ + C24 ++ + +: <30%, ++: 30-75%, +++: >75%; ND: not determined

[0400] These data illustrate the use of these compounds as prodrugs, as they are converted to 3APS in the blood.

Example 3: Pharmacokinetics in Mice

A. Bioavailability of Exemplary Compounds

[0401] Selected exemplary compounds were tested for bioavailability in mice. Bioavailability estimates are performed for 3APS after administration of molar equivalent the selected compounds. At a specific time point following drug administration, one blood sample (approximately 1 ml) is collected from each of 3 animals from the inferior vena cava. The animals are anesthetized with isoflurane before blood collection (approximately 45 sec).

[0402] Samples are collected at 5, 30, 60, 120, 180, 240 and 360 min post intravenous administration and at 15, 30, 60, 120, 180, 240 and 360 min post oral administration. One animal is used to obtain a baseline sample (pre-dose sample). Blood samples are collected into Sarstedt™ micro tubes (EDTA KE/1.3 ml), kept on ice until centrifugation at 4° C. at a minimum speed of 3000 rpm (1620G) for 10 min. Plasma samples are transferred into Eppendorf™ tubes, immediately placed on dry ice and stored at −80° C. Plasma samples are stored frozen at −20° C. pending analysis.

[0403] Compounds in mouse plasma are extracted using protein precipitation. Quantitation of 3APS in mouse plasma matrix is achieved using LC-MS detection. Sample concentration is calculated using a calibration curve. Bioavailability results are summarized in Table 9.

TABLE-US-00010 TABLE 9 Bioavailability of selected compounds in mice Bioavailability (F) in mice * ID (+: <25%, ++: 25-35%, +++: >35%) A (3APS) ++ A1 ++ A2 +++ A3 + A4 +++ A6 ++ A7 +++ A13 +++ A18 +++ C9 + C13 + C14 + C15 + C16 + C17 + C18 + C19 ++ C21 + C22 + C25 + * Calculated from the concentration of 3APS, 6 hours after administration of the tested compound. The calculated F value represents the Ratio (in percentage) of the AUC p.o. of the compound tested over the AUC i.v. of 3APS, based on the observation of 3APS.

[0404] As shown in Table 9, all the compounds tested were capable of delivering measurable quantities of 3APS. Compounds A2, A4, A7 and A18 were helpful in increasing the bioavailability of 3APS suggesting that they were more readily absorbed than 3APS or were able to prevent first-pass metabolism of 3APS. Although not shown, Compounds A3, C13, C14, C16, C17, C21, C22 and C25 had a measured T.sub.max 4 times to 16 times longer that 3APS (0.25h), suggesting a significant improvement in the pk profiles of 3APS using those compounds.

B. PK Brain and Plasma Levels of Oral Compound A2 and 3-APS

[0405] Compounds A2 and 3-aminopropanesulfonic acid were tested for pharmacokinetic parameters in mice. Parmacokinetic parameters (Cmax, Tmax, T1/2, AUC) are evaluated for 3APS after administration of a molar equivalent of each compound. Blood samples (approximately 1 ml) and brain samples are collected from each of 3 animals at time points 5, 15, 30 minutes, 1, 2, 4, 6, 12, and 24 hours. The results analyzed from plasma samples and brain homogenates are summarized in Table 10. Relative bioavailability (F %) of Compound A2 and 3-APS were respectively of 51% and to 32%. A 2-fold increase in plasma concentration (Cmax) of 3-APS was observed when orally administering Compound A2 compared to 3-APS. Brain concentration of 3-APS was observed after oral administration of 0.18 mmol/kg for Compound A2, whereas the concentration could not be quantified after oral administration of the same molar equivalent of 3-APS.

TABLE-US-00011 TABLE 10 PK data on 3-APS analysis following oral administration of 25 mg/kg (0.18 mmol/kg) and 250 mg/kg (1.80 mmol/kg) equivalent of 3-APS Plasma Brain Dose Cmax Tmax T½ Cmax Tmax T½ ID (mmol/kg) AUC (ng/mL) (h) (h) AUC (ng/mL) (h) (h) 3-APS 0.18 6427 1768 0.5 4.9 BLLQ BLLQ N/A N/A A2 0.18 10135 3435 0.5 2.8  557  148 2.0  3.9 A2 1.80 140661 35451 0.5 2.8 9772 1068 2.0 12.4 BLLQ: below the lower limit of quantification N/A: not applicable

Example 4: Pharmacokinetic Analysis of 3APS and Associated Metabolism

Example 4A: Metabolic Profiling of .SUP.14.C-3APS in Mice, Rats and Dogs

[0406] Three single dose studies were conducted in mice, rats and dogs to determine the metabolic profile of .sup.14C-3APS in plasma, urine and feces. In the first study, twenty-seven male CD-1 mice received a single dose of 100 mg/kg (20 μCi/animal) of .sup.14C-3APS by oral gavage. Blood samples (3 animals/time point) were collected for 12 hr following drug administration while urine and feces (3 animals/time point) samples were collected for 96 hr. In the second study, eight male Sprague-Dawley rats received a single dose of 100 mg/kg (50 μCi/animal) of .sup.14C-3APS by oral gavage while in the third study, three male Beagle dogs received a single dose of 100 mg/kg (30 μCi/kg) of .sup.14C-3APS by oral gavage. For the rat and dog studies, blood samples were collected for 24 hr following drug administration while urine and feces samples were collected for 72 hr. All samples were analyzed for total radioactivity using appropriate sample preparation procedures and scintillation counting. Plasma and urine samples were also analyzed for SAPS and 3APS metabolites (2-carboxyethanesulfonic acid, 3-hydroxy-1-propanesulfonic acid and 3-acetylamino-1-propanesulfonic acid) concentrations using qualified HPLC and MS/MS methods.

[0407] Following oral administration of 100 mg/kg .sup.14C-3APS to mice and rats, mean maximum plasma concentrations of total radioactivity and 3APS were reached at approximately 30 minutes post-dose (Table 11). Thereafter, plasma concentrations of total radioactivity and 3APS declined in a multi-phasic manner with apparent terminal half-lives of approximately 2 and 6 h for mice and rats, respectively. Mean maximum plasma concentration of 2-carboxyethanesulfonic acid was achieved at 120 to 240 h post-dose. Thereafter, plasma concentrations declined in a multi-phasic manner with an apparent terminal half-life of approximately 2 h and 4 h for mice and rats, respectively.

[0408] Following oral administration of 100 mg/kg .sup.14C-3APS to dogs, maximum plasma concentration of total radioactivity and 3APS were reached at approximately 30 minutes post-dose, whereas maximum plasma concentration of 2-carboxyethanesulfonic acid was achieved at 720 minutes post-dose (Table 11). Thereafter, plasma concentrations of total radioactivity and 3APS declined in a multi-phasic manner. The mean apparent terminal half-lives were approximately 35 h and 5 h for total radioactivity and 3APS, respectively.

[0409] For all species, the majority of total radioactivity was associated with 3APS and 2-carboxyethanesulfonic acid (Table 12). Based on AUC.sub.0−∞ values, 3APS accounted for approximately 60% of total radioactivity while 2-carboxyethanesulfonic acid accounted for 30% in mice and rats. In dogs, 3APS accounted for approximately 54% of total radioactivity while 2-carboxyethanesulfonic acid accounted for approximately 67%. 3APS and 2-carboxyethanesulfonic acid AUC.sub.0−∞ constituted approximately 90% (mouse and rat) and approximately 121% (dog) of the total radioactivity indicating that 2-carboxyethanesulfonic acid is the major metabolite of 3APS in the mouse, rat and dog.

[0410] For all species, total radioactivity was quantitatively recovered in urine and feces with approximately 75 to 90% of the administered dose recovered in 72 h (rat and dog) or 96 h (mouse). The major route of excretion of total radioactivity was via urine.

[0411] On average, 60% of the dose was excreted in urine as total radioactivity in all species. Based on the total amount of radioactivity excreted in urine, approximately 30% was excreted as 3APS while 2-carboxyethanesulfonic acid accounted for another 63% to 77% in mouse and dog. In rats, 3APS and 2-carboxyethanesulfonic acid accounted for 59% and 62% of total radioactivity, respectively. On average the two metabolites 3-hydroxy-1-propanesulfonic acid and 3-acetylamino-1-propanesulfonic acid represented less than 3% of the total radioactivity in all species (Table 11). The urinary cumulative amount of 3APS and 2-carlDoxyethanesulfonic acid accounted for approximately 90 to 110% of that determined for total radioactivity, once again suggesting that 2-carboxyethanesulfonic acid is the major metabolite of 3APS in the mouse, rat and dog.

TABLE-US-00012 TABLE 11 Pharmacokinetic Parameters of Total Radioactivity, 3APS and 2-carboxyethanesulfonic acid Following Single Oral Administration of 100 mg/kg .sup.14C-3APS in Mice, Rats and Dogs Parameter Mouse.sup.1 Rat Dog Total Radioactivity C.sub.max (μmol eq/mL) 0.126 0.228 0.249 T.sub.max (min) 30 30 31 AUC.sub.0-τ (μmol eq .Math. min/mL) 24.4 43.3 45.4 AUC.sub.∞ (μmol eq .Math. min/mL) 25.0 45.2 108 T.sub.1/2 (h) 2.14 6.02 35.7 3APS C.sub.max (μmol/mL) 0.0977 0.218 0.250 T.sub.max (min) 30 30 31 AUC.sub.0-τ (μmol .Math. min/mL) 15.5 26.7 24.5 AUC.sub.∞ (μmol .Math. min/mL) 15.7 27.6 25.3 T.sub.1/2 (h) 1.72 6.43 5.04 2-carboxyethanesulfonic acid C.sub.max (μmol/mL) 0.018 0.0234 0.0312 T.sub.max (min) 120 240 720 AUC.sub.0-τ (μmol .Math. min/mL) 7.26 12.7 30.5 AUC.sub.∞ (μmol .Math. min/mL) 7.56 13.6 NC T.sub.1/2 (h) 2.33 3.99 NC .sup.1PK parameters were derived using the mean plasma concentration-time profiles NC: Not calculated

TABLE-US-00013 TABLE 12 Percentage of 3APS, 2-carboxyethanesulfonic acid, 3-acetylamino- 1-propanesulfonic acid and 3-hydroxy-1-propanesulfonic acid in Plasma and Urine Following Single Oral Administration of 100 mg/kg .sup.14C-3APS in Mice, Rats and Dogs % of Total Radioactivity 2-carboxy- 3-acetylamino- 3-hydroxy- ethane- 1-propane- 1-propane- sulfonic sulfonic sulfonic 3APS acid acid acid Mouse Plasma* 63 30 — — Urine.sup.† 30 62 3.1 0.4 Rat Plasma* 61 30 — — Urine.sup.† 59 62 2.3 0.3 Dog Plasma* 54 67 — — Urine.sup.† 29 77  0.01 0.3 *Calculated as [AUC0-∞ 3APS or metabolites/AUC total radioactivity)] (or using AUC0-t if AUC0-∞ could not be reliably estimated) .sup.†Calculated as [Amount Excreted 3APS or metabolites/AUC total radioactivity)]

Example 4B: Absorption, Excretion and Plasma Kinetics of .SUP.14.C-3APS in Humans

[0412] Following the identification of 3APS metabolites, plasma and urine samples from this human AME study were reanalyzed for 3APS and 3APS metabolite (2-carboxyethanesulfonic acid, 3-hydroxy-1-propanesulfonic acid and 3-acetylamino-1-propanesulfonic acid) concentrations using qualified HPLC and MS/MS methods to determine the metabolic profile of .sup.14C-3APS in human.

[0413] Following oral administration of .sup.14C-3APS to healthy subjects, maximum plasma concentration of total radioactivity and 3APS were reached at approximately 1 to 1.25 hours post-dose, whereas maximum plasma concentration of 2-carboxyethanesulfonic acid was achieved at 6.5 hours. In plasma, the majority of total radioactivity was associated with 3APS and 2-carboxyethanesulfonic acid. Based on AUC.sub.0−τ values, 3APS accounted for approximately 48% of total radioactivity while 2-carboxyethanesulfonic acid accounted for 49%. 3APS and 2-carboxyethanesulfonic acid AUC.sub.0−τ constituted approximately 97% of the total radioactivity indicating that 2-carboxyethanesulfonic acid is the major metabolite of 3APS in human plasma.

[0414] Based on the total amount of radioactivity excreted in urine, approximately 15% was excreted as 3APS while 2-carboxyethanesulfonic acid accounted for another 79%. The urinary cumulative amount of 3APS and 2-carboxyethanesulfonic acid accounted for approximately 94% of that determined for total radioactivity, once again suggesting that 2-carboxyethanesulfonic acid is the major metabolite of 3APS.

Example 4C: Comparative Pharmacokinetic Parameters of SAPS and 2-carboxyethanesulfonic Acid Following a Single Oral and IV Administration of .SUP.14.C-3APS to Rats

[0415] The purpose of this study was to investigate the absorption, metabolism and excretion profiles of .sup.14C-3APS following a single intravenous bolus and oral administration to rats. Thirty-six male Sprague-Dawley rats received a single 100 mg/kg (˜50 μCi/animal) dose of .sup.14C-3APS by an IV bolus injection (water or isotonic saline solution) and an additional 36 male rats received the same dose level by oral gavage (in water). Blood, urine, feces, brain and CSF samples were collected for up to 72 hr following dose administration. Plasma, urine, brain and CSF concentrations of 3APS and 2-carboxyethanesulfonic acid (3APS major metabolite) were measured using LC and MS/MS detection method. Plasma, urine, feces, brain and CSF samples were analyzed for total radioactivity using appropriate sample preparation procedures and scintillation counting.

[0416] Based on AUC.sub.0−∞ values, after IV administration, 3APS accounted for 89% of total radioactivity and 2-carboxyethanesulfonic acid only about 9%. On the other hand, after oral administration, 3APS accounted for about 68% of total radioactivity and 2-carboxyethanesulfonic acid about 26%. Using those data, it is possible to calculate a metabolite-to-parent ratio of the exposure of about 0.1 following IV administration and a ratio of 0.38 following oral administration. This higher metabolite-to-parent ratio of the exposure following oral administration when compared to IV is consistent with an intestinal first-pass metabolism.

TABLE-US-00014 TABLE 13 Comparison of Systemic Exposure of 3APS and 2-carboxyethanesulfonic acid versus Total Radioactivity following a Single IV and Oral Administration of 14C-3APS in Rats AUC.sub.0-∞(nmol .Math. h/mL).sup.# % (3APS and 2-carboxy- % (2-carboxy- 2-carboxy- ethane- Total ethane- ethane- sulfonic Radio- sulfonic sulfonic Animal 3APS acid activity acid)* acid)** IV 1001 1528 105 1625 6.5 100.5 1002 1420 144 1588 9.1 98.5 1003 1591 184 1883 9.8 94.3 1004 1147 125 1266 9.9 100.5 Mean 1422 140 1591 8.8 98.4 ±SD 196.2 33.7 253.0 1.60 2.93 % CV 13.8 24.1 15.9 18.1 2.98 PO 3001 610 232 874 26.5 96.3 3002 539 153 714 21.4 96.9 3003 407 177 628 28.2 93.0 3004 471 229 781 29.3 89.6 Mean 507 198 749 26.4 94.0 ±SD 87.4 39.1 104 3.49 3.37 % CV 17.3 19.8 13.9 13.2 3.59 .sup.#AUC.sub.0-∞ expressed as nmol eq .Math. h/mL for total radioactivity *Calculated as [(AUC.sub.0-∞ 2-carboxyethanesulfonic acid/AUC total radioactivity)*100] **Calculated as [(AUC.sub.0-∞ 3APS + AUC.sub.0-∞ 2-carboxyethanesulfonic acid)/AUC total radioactivity] *100

Example 4D: Comparative Pharmacokinetics Parameters of 3APS and 2-carboxyethanesulfonic acid Following a Single Oral, Intravenous and Portal Administration of 3APS in Rats

[0417] The purpose of this study was to compare the pharmacokinetic profile of 3APS following a single dose administration either orally, intravenously or into the portal vein to male Sprague-Dawley rats. The oral, intravenous and portal routes of administration were selected to determine the intestinal and hepatic first-pass effects in the rat. Three groups of 4 male Sprague-Dawley rats were assigned to receive a single dose of 250 mg/kg 3APS by different routes of administration. One group received 3APS as an IV bolus administration (in water or isotonic saline solution), one group by oral gavage (in water) and the last group via a catheter into the portal vein (in water or isotonic saline solution). Blood samples were collected for 24 hours following dose administration. Plasma concentrations of 3APS and 2-carboxyethanesulfonic acid (the major metabolite of 3APS) were determined using LC and MS/MS method.

[0418] Following oral administration, maximum plasma concentrations (C.sub.max) were generally reached within 1 hour for 3APS and its bioavailability based on the AUC.sub.∞ was calculated to be about 38%.

[0419] The results obtained confirmed that there is an important metabolism of 3APS. More particularly, based on a comparison between the systemic exposures following hepatoportal and intravenous administrations, metabolism of 3APS associated with hepatic first-pass was estimated to be 24%. By comparison between the systemic exposures following oral and hepatoportal administrations, metabolism of 3APS associated with intestinal first-pass was estimated to be 43%. This study also showed that the oral administration of 3APS generated 50% more metabolite than the intravenous administration which is consistent with an intestinal first-pass metabolism.

Example 5: In Vitro Metabolism of 3APS in Primary Rat Neuron Culture and Organotypic Hippocampal Slice Culture

[0420] The metabolism of 3APS was also studied in vitro in different types of cellular models. In some cases, the metabolism of 3APS was compared with that of γ-amino butyric acid (GABA).

[0421] The results obtained demonstrated that incubation of 3APS (400 μM) in primary rat neuron culture media produced 2-carboxyethanesulfonic acid as a metabolite. The conversion of 3APS to 2-carboxyethanesulfonic acid was time-dependent and cell concentration-dependent. Incubation of 3APS (400 μM initial concentration) for six days in the cell culture media (containing 800,000 cells) produced with 48 μM of 2-carboxyethanesulfonic acid. Under the same experimental conditions, 5.4 μM succinic acid was detected starting from GABA (400 μM initial concentration).

[0422] The conversion of 3APS to 2-carboxyethanesulfonic acid in the primary neuron culture media was significantly inhibited by vigabatrin, the latter a classic GABA transaminase inhibitor. Nialamide, a monoamine oxidase inhibitor, also reduced the formation of 2-carboxyethanesulfonic acid (from 3APS) but to a lesser extent. In contrast, gabapentin (known to increase GABA concentration in the brain) had no significant effect on the conversion of 3APS to 2-carboxyethanesulfonic acid.

[0423] In another in vitro model employing organotypic hippocampal slice culture, the conversion of 3APS to 2-carboxyethanesulfonic acid was time-dependent. More than 60% of 3APS was converted to 2-carboxyethanesulfonic acid after 3-day incubation in the culture media. 2-carboxyethanesulfonic acid was also detected after incubation of 3APS in human hepatocyte (HepG2) culture media.

[0424] It is understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application and scope of the appended claims.