ANTICONVULSANT CARBAMATE DERIVATIVES

Abstract

The invention contemplates novel materials as anticonvulsant agents.

Claims

1. A compound comprising a 4-sulfamoylphenyl carbamate moiety and an alkyl moiety comprising between 5 and 10 carbon atoms.

2. The compound according to claim 1, wherein the alkyl moiety is a straight or branched alkyl group comprising 5, 6, 7, 8, 9, or 10 carbon atoms.

3. The compound according to claim 1, wherein the alkyl moiety is selected from the group consisting of a substituted or unsubstituted pentyl moiety, a substituted or unsubstituted hexyl moiety, a substituted or unsubstituted heptyl moiety, a substituted or unsubstituted octyl moiety, a substituted or unsubstituted nonyl moiety and a substituted or unsubstituted decyl moiety, provided that the number of carbon atoms in the moiety does not exceed 10 atoms.

4. The compound according to claim 1, wherein the alkyl moiety is selected from the group consisting of 3-methyl-2-propylpentyl, 2-ethylhexyl, 2-propylpentyl, 3,3-dimethylbutyl, phenethyl, 2-ethylbutyl, 2,4,4-trimethylpentyl, 2,4-dimethylpentan-3-yl, 3-methylpentan-2-yl and 3-methylpentyl.

5. The compound according to claim 1, being of formula (I): ##STR00006## wherein A is an alkyl moiety.

6. The compound according to claim 1, being selected from the group consisting of 3-methyl-2-propylpentyl (4-sulfamoylphenyl)carbamate (1); 2-ethylhexyl (4-sulfamoylphenyl)carbamate (2); 2-propylpentyl (4-sulfamoylphenyl)carbamate (3); 3,3-dimethylbutyl (4-sulfamoylphenyl)carbamate (4); phenethyl (4-sulfamoylphenyl)carbamate (5); 2-ethylbutyl (4-sulfamoylphenyl)carbamate (6); 2,4,4-trimethylpentyl (4-sulfamoylphenyl)carbamate (7); 2,4-dimethylpentan-3-yl (4-sulfamoylphenyl)carbamate (8); 3-methylpentan-2-yl (4-sulfamoylphenyl)carbamate (9) and 3-methylpentyl(4-sulfamoylphenyl)carbamate (10).

7. The compound according to claim 6, being compound (1), (2), (3), (4), (5), (6), (7), (8), (9) or (10).

8. The compound according to claim 6, being compound (1) or (9) or (10).

9. A composition comprising a compound of claim 1.

10. The composition according to claim 9, being a pharmaceutical composition.

11. A method of treatment of a neurological disease or disorder, the method comprising administering to a subject in need of such treatment an effective amount of a compound selected from the group consisting of 3-methyl-2-propylpentyl (4-sulfamoylphenyl)carbamate (1); 2-ethylhexyl (4-sulfamoylphenyl)carbamate (2); 2-propylpentyl (4-sulfamoylphenyl)carbamate (3); 3,3-dimethylbutyl (4-sulfamoylphenyl)carbamate (4); phenethyl (4-sulfamoylphenyl)carbamate (5); 2-ethylbutyl (4-sulfamoylphenyl)carbamate (6); 2,4,4-trimethylpentyl (4-sulfamoylphenyl)carbamate (7); 2,4-dimethylpentan-3-yl (4-sulfamoylphenyl)carbamate (8); 3-methylpentan-2-yl (4-sulfamoylphenyl)carbamate (9), 3-methylpentyl(4-sulfamoylphenyl)carbamate (10) and sec-butyl(4-sulfamoylphenyl)carbamate (11).

12. The method according to claim 11, wherein the neurological disease or disorder is selected from the group consisting of epilepsy, convulsions, seizure disorder, complex partial seizures, status epilepticus, a chemically-induced convulsion and/or seizure disorder, a febrile convulsion condition, pain and psychiatric disorders.

13. An anticonvulsant agent comprising a compound selected from the group consisting of 3-methyl-2-propylpentyl (4-sulfamoylphenyl)carbamate (1); 2-ethylhexyl (4-sulfamoylphenyl)carbamate (2); 2-propylpentyl (4-sulfamoylphenyl)carbamate (3); 3,3-dimethylbutyl (4-sulfamoylphenyl)carbamate (4); phenethyl (4-sulfamoylphenyl)carbamate (5); 2-ethylbutyl (4-sulfamoylphenyl)carbamate (6); 2,4,4-trimethylpentyl (4-sulfamoylphenyl)carbamate (7); 2,4-dimethylpentan-3-yl (4-sulfamoylphenyl)carbamate (8); 3-methylpentan-2-yl (4-sulfamoylphenyl)carbamate (9), 3-methylpentyl(4-sulfamoylphenyl)carbamate (10) and sec-butyl(4-sulfamoylphenyl)carbamate (11).

14. A method of treatment comprising administering to a subject an anticonvulsant agent according to claim 13.

15. A kit comprising an anticonvulsant agent selected from the group consisting of 3-methyl-2-propylpentyl (4-sulfamoylphenyl)carbamate (1); 2-ethylhexyl (4-sulfamoylphenyl)carbamate (2); 2-propylpentyl (4-sulfamoylphenyl)carbamate (3); 3,3-dimethylbutyl (4-sulfamoylphenyl)carbamate (4); phenethyl (4-sulfamoylphenyl)carbamate (5); 2-ethylbutyl (4-sulfamoylphenyl)carbamate (6); 2,4,4-trimethylpentyl (4-sulfamoylphenyl)carbamate (7); 2,4-dimethylpentan-3-yl (4-sulfamoylphenyl)carbamate (8); 3-methylpentan-2-yl (4-sulfamoylphenyl)carbamate (9), 3-methylpentyl(4-sulfamoylphenyl)carbamate (10) and sec-butyl(4-sulfamoylphenyl)carbamate (11).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0119] In order to better understand the subject matter that is disclosed herein and to exemplify how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

[0120] FIG. 1 depicts the structures of exemplary compounds of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

[0121] A novel series of carbamate derivatives containing 4-aminobenzenesulfonamide and branched VPA or phenethyl moieties were synthesized in good yields and screened for their anticonvulsant activities in MES and scMet and 6 Hz test. In mice compounds 1, 9, 10 and 11 had ED.sub.50 values of 236 mg/kg, 31 mg/kg, 14 mg/kg and 75 mg/kg (MES) and 74 mg/kg, 53 mg/kg, 88 mg/kg (6 Hz), respectively. Compounds 1, 9, 10 and 11 had rat (po)-MES-ED.sub.50 values of 36 mg/kg, 28 mg/kg, 23 mg/kg and 25 mg/kg, respectively. These potent carbamates induced neural tube defects only at doses markedly exceeding their anticonvuslnat-ED.sub.50 values. None of these compounds were potent inhibitors of CA IV, but inhibited isoforms CAs I, II and VII. All three of these compounds (and particularly compound 10) exhibited better protective index than VPA.

[0122] Materials and Methods

[0123] Chemistry.

[0124] Unless otherwise stated, all reagents were purchased from commercial suppliers and used without further purification. Solvents used in the reactions were distilled from appropriate drying agents prior to use.

[0125] General Procedure for the Synthesis of Compounds.

[0126] The general syntheses for the 4-aminobenzenesulfonamides derivatives in Scheme 1. A solution of the alcohol (1 equiv) in dichloromethane (DCM, 5 mL) was added dropwise to a stirred solution of triphosgene (0.5 equiv) and pyridine (1 equiv) in DCM (10 mL). The reaction mixture was allowed to stir for 2 hr and then was evaporated. The residue was dissolved in THF (10 mL). A solution of sulfanilamide (500 mg) in THF (10 mL) was added and stirred overnight. The reaction was quenched with water and extracted with EtOAc (15 mL). The organic layer was washed with water and brine, dried over sodium sulfate, filtered, and concentrated in vacuo. The desired product was obtained following flash chromatography (EtOAc/hexane). The compounds designed in this study were synthesized by non-stereospecific methods and thus evaluated as racemates.

3-methyl-2-propylpentyl (4-sulfamoylphenyl)carbamate (1)

[0127] White powder; mp 151-152 C. .sup.1H NMR (300 MHz, DMSO-d.sub.6) 9.94 (s, 1H), 7.76-7.65 (m, 2H), 7.65-7.54 (m, 2H), 7.19 (s, 2H), 4.15-3.92 (m, 2H), 3.36-3.23 (m, 1H), 1.56-1.04 (m, 7H), 0.92-0.77 (m, 9H). Calcd for C16H26N2O4S: C, 56.12; H, 7.65; N, 8.18; S, 9.36. Found: C, 56.12; H, 7.76; N, 8.0; S, 9.08.

2-ethylhexyl (4-sulfamoylphenyl)carbamate (2)

[0128] White powder; mp 192-195 C. .sup.1H NMR (300 MHz, DMSO-d.sub.6) , 8.10 (s, 1H), 7.39 (d, J=8.6 Hz, 2H), 7.26 (s, 2H), 7.04 (d, J=8.6 Hz, 1H), 4.29 (m, 2H), 1.62-1.68 (m, 1H), 1.44-1.23 (m, 8H), 0.99-0.80 (m, 6H). Calcd for C15H24N2O4S: C, 58.86; H, 7.37; N, 8.53; S, 9.76. Found: C, 56.62; H, 7.09; N, 8.57; S, 9.58.

2-propylpentyl (4-sulfamoylphenyl)carbamate (3)

[0129] White powder; mp 176-177 C. .sup.1H NMR (300 MHz, DMSO-d.sub.6) 9.92 (s, 1H), 7.76-7.65 (d, J=8.6 Hz, 2H), 7.65-7.54 (d, J=8.7 Hz, 1H), 7.17 (s, 2H), 4.00 (m, 2H), 1.66 (s, 1H), 1.42-1.18 (m, 8H), 0.97-0.81 (m, 6H). Calcd for C15H24N2O4S: C, 54.86; H, 7.37; N, 8.53; S, 9.76. Found: C, 55.05; H, 7.28; N, 8.43; S, 9.54.

3,3-dimethylbutyl (4-sulfamoylphenyl)carbamate (4)

[0130] White powder; mp 170-173 C. .sup.1H NMR (300 MHz, DMSO-d.sub.6) 9.99 (s, 1H), 7.67-7.74 (d, J=8.7 Hz, 2H), 7.63-7.5 (d, J=8.7 Hz, 2H), 7.21 (s, 2H), 4.11 (m, 2H), 1.57-1.48 (m, 2H) 0.96 (s, 9H). Calcd for C13H20N2O4S: C, 51.98; H, 6.71; N, 9.33; S, 10.68. Found: C, 52.03; H, 6.66; N, 9.2; S, 10.33.

phenethyl (4-sulfamoylphenyl)carbamate (5)

[0131] White powder; mp 212-213 C. .sup.1H NMR (300 MHz, DMSO-d.sub.6) 10.02 (s, 1H), 7.56-7.63 (d, J=8.6 Hz, 2H), 7.68-7.72 (d, J=8.6 Hz, 2H), 7.29 (s, 2H), 7.31-7.19 (m, 5H), 4.41 (t, J=6.8 Hz, 2H), 2.84 2.95 (t, J=6.8 Hz, 2H). Calcd for C15H16N2O4S: C, 56.24; H, 5.03; N, 8.74; S, 10.01. Found: C, 55.9; H, 5.07; N, 8.61; S, 9.64.

2-ethylbutyl (4-sulfamoylphenyl)carbamate (6)

[0132] White powder; mp 162-165 C. .sup.1H NMR (300 MHz, DMSO-d.sub.6) 9.92 (s, 1H), 7.58-7.62 (d, J=8.9 Hz, 2H), 7.68-7.72 (d, J=8.9 Hz, 2H), 7.21 (s, 2H), 4.02 (m, 2H), 2.07 (s, 1H), 1.36 (m, 1H), 1.05-0.87 (m, 6H). Calcd for C13H20N2O4S: C, 51.98; H, 6.71; N, 9.33; S, 10.68. Found: C, 51.59; H, 6.65; N, 9.18; S, 10.54.

2,4,4-trimethylpentyl (4-sulfamoylphenyl)carbamate (7)

[0133] White powder; mp 199-201 C. .sup.1H NMR (300 MHz, DMSO-d.sub.6) 9.96 (s, 1H), 7.76-7.65 (d, J=8.7 Hz, 1H), 7.65-7.54 (d, J=8.7 Hz, 1H), 7.18 (s, 2H), 3.97 (m, 1H), 3.79 (m, 1H), 1.83 (m, 1H), 1.92-1.76 (m, 1H), 1.29 (m, 1H), 1.00 (m, 4H), 0.89 (s, 8H). Calcd for C15H24N2O4S: C, 54.86; H, 7.37; N, 8.53; S, 8.76. Found: C, 54.48; H, 7.29; N, 8.31; S, 8.39.

2,4-dimethylpentan-3-yl (4-sulfamoylphenyl)carbamate (8)

[0134] White powder; mp 193-194 C. .sup.1H NMR (300 MHz, DMSO-d.sub.6) 9.94 (s, 1H), 7.70 (d, J=8.6 Hz, 2H), 7.60 (d, J=8.7 Hz, 2H), 7.20 (s, 2H), 4.43 (t, J=6.2 Hz, 1H), 1.90 (h, J=7.0 Hz, 2H), 0.87 (d, J=6.7 Hz, 12H). Calcd for C14H22N2O4S: C, 53.48; H, 7.05; N, 8.91; S, 10.20. Found: C, 53.42; H, 7.25; N, 8.62; S, 9.93.

3-methylpentan-2-yl (4-sulfamoylphenyl)carbamate (9)

[0135] White powder; mp 179-180 C. .sup.1H NMR (300 MHz, DMSO-d.sub.6) 9.90 (s, 1H), 7.57-7.61 (d, J=8.7 Hz, 1H), 7.68-7.71 (d, J=8.7 Hz, 1H), 7.18 (s, 2H), 4.82-4.63 (m, 1H), 1.65-1.41 (m, 1H), 1.17 (m, 5H), 0.88 (m, 6H). Calcd for C13H20N2O4S: C, 51.98; H, 6.71; N, 9.33; S, 10.68. Found: C, 52.03; H, 6.61; N, 9.32; S, 11.2.

3-methylpentyl(4-sulfamoylphenyl)carbamate (10)

[0136] White powder; mp 168-169 C. .sup.1H NMR (300 MHz, DMSO-d.sub.6) 10.00 (s, 1H), 7.70 (d, J=8.8 Hz, 2H), 7.59 (d, J=8.7 Hz, 2H), 7.20 (s, 1H), 4.18-4.07 (m, 2H), 1.73-1.56 (m, 1H), 1.11-1.21 (m, 4H), 0.85 (m, 6H).

[0137] Calcd for C13H20N2O4S: C, 51.98; H, 6.71; N, 9.33; S, 10.68. Found: C, 52.12; H, 6.54; N, 9.35; S, 10.77.

sec-butyl(4-sulfamoylphenyl)carbamate (11)

[0138] White powder; mp 190-191 C. .sup.1H NMR (300 MHz, DMSO-d.sub.6) 9.97 (s, 1H), 7.69 (d, J=8.8 Hz, 2H), 7.60 (d, J=8.7 Hz, 2H), 7.20 (s, 2H), 4.77-4.68 (m, 1H), 1.63-1.53 (m, 2H), 1.23-1.21 (d, 3H), 0.92-0.87 (t, 3H). Calcd for C11H16N2O4S: C, 48.52; H, 5.92; N, 10.29; S, 11.77. Found: C, 48.47; H, 6.02; N, 10.13; S, 11.56.

[0139] Materials and Methods.

[0140] Product formation follow-up was performed by means of .sup.1H NMR and TLC. TLC analyses were performed on pre-coated silica gel on aluminum sheets (Kieselgel 60 F254, Merck). .sup.1H NMR spectra were recorded on a Varian Mercury series NMR 300 spectrometer. Chemical shifts (6 scale) are reported in parts per million (ppm) relative to the indicated reference. Coupling constants are given in Hz. Chemical structure and purity of the compounds newly synthesized was assessed by TLC, .sup.1H NMR and HPLC. Melting point was determined on a 1002-230 VAC Mel-Temp capillary melting point apparatus.

[0141] Biological Testing/Anticonvulsant Activity.

[0142] The evaluation of anticonvulsant activity in the maximal electroshock seizure test (MES), subcutaneous metrazol seizure test (scMet) and 6 Hz psychomotor test (6 Hz), corneal kindled mouse (CKM) and the determination of minimal neurotoxicity using the rotarod test and positional sense test and others were performed at the National Institute of Health (NIH)-National Institute of Neurological Disorders and Stroke (NINDS) as a part of the Epilepsy Therapy Screening Program (ETSP) according protocols described in [22] and [23].

[0143] Preparation of the Compounds for Testing.

[0144] The tested compounds were suspended in 0.5% methylcellulose and administered intraperitoneally (i.p.) to adult male CF no. 1 albino mice (18-25 g) in a volume of 0.01 mL/g body weight and (b) orally to adult male Sprague-Dawley albino rats (100-150 g) in a volume of 0.04 mL per 10 g of body weight. The pentylenetetrazol solution at convulsing dose was prepared by sufficient dissolution of pentylenetetrazol in 0.9% saline to make 0.85% solution for administration to mice and 2.82% solution for administration to rats [22, 23].

[0145] Determination of the Median Effective Dose (ED.sub.50) and the Median Neurotoxic Dose ((TD.sub.50).

[0146] Dose (ED.sub.50 & TD.sub.50).

[0147] For the determination of the ED.sub.50 by the respective anticonvulsant procedure, doses of the tested compounds were varied until a minimum of 3-4 points was established between the dose level with 0% protection and 100% protection. These data were subjected to the FORTRAN probit analysis program, and the ED.sub.50 and 95% confidence intervals were calculated. The TD.sub.50 was determined by varying the dose of the tested compounds until four points were established between the dose level that induced no signs of minimal motor impairment in any of the animals and the dose at which all of the animals were considered impaired. The TD.sub.50 and the 95% confidence intervals were calculated by FORTRAN probit analysis. The PI values were calculated by dividing the TD.sub.50 by the ED.sub.50 [22, 23].

[0148] Evaluation of Teratogenicity.

[0149] The teratogenic properties of the newly designed compounds (1-10) were evaluated in the highly inbred SWV mice strain known for its high susceptibility to VPA-induced neural tube defects (NTDs) [24, 25]. Two month old nulligravid females, were mated overnight with males and examined for the presence of vaginal plugs the following morning, and the onset of gestation was considered to be 10 p.m. of the previous night, the midpoint of the dark cycle. At day 8.5 of gestation, each dam received a single i.p. injection of the test compounds in an equimolar dose of 0.9 or 1.8 mmol/kg and the control dams were injected with vehicle (25% water solution of Cremophore EL, Fluka Biochemica Germany). The volume of injection was 10 L/g of body weight. The 1.8 mmol/kg dose was selected as this was the highest dose that did not produce overt maternal toxicity except for deep sedation and lack of ambulation lasting for approximately 2 hours post-injection. At gestation day 8.5, the dams were euthanized by carbon dioxide asphyxiation followed by cervical dislocation. After the opening the uterus, the location of all viable fetuses and resorption sites were recorded, and the fetuses were examined for the presence of exencephaly or other gross congenital abnormalities. The teratogenicity data (implantations, resorptions and NTDs) were evaluated for significant differences between the control and treated groups by analyzing the contingency table with Fisher's exact test. Statistical analysis was conducted using GraphPad InStat (version 3.06; GraphPad Software, San Diego, Calif., USA), and the results of all tests were considered to be statistically significant when the p-value was less than 0.05

[0150] CA Inhibition.

[0151] An Applied Photophysics stopped-flow instrument has been used for assaying the CA catalysed CO.sub.2 hydration activity [26]. Phenol red (at a concentration of 0.2 mM) has been used as indicator, working at the absorbance maximum of 557 nm, with 20 mM Hepes (pH 7.5) as buffer, and 20 mM Na.sub.2SO.sub.4 (for maintaining constant the ionic strength), following the initial rates of the CA-catalyzed CO.sub.2 hydration reaction for a period of 10-100 s. The CO.sub.2 concentrations ranged from 1.7 to 17 mM for the determination of the kinetic parameters and inhibition constants. For each inhibitor at least six traces of the initial 5-10% of the reaction have been used for determining the initial velocity. The uncatalyzed rates were determined in the same manner and subtracted from the total observed rates. Stock solutions of inhibitor (0.1 mM) were prepared in distilled-deionized water and dilutions up to 0.01 nM were done thereafter with the assay buffer. Inhibitor and enzyme solutions were preincubated together for 15 min at room temperature prior to assay, in order to allow for the formation of the E-I complex. The inhibition constants were obtained by non-linear least-squares methods using PRISM 3 and the Cheng-Prusoff equation, as reported earlier and represent the mean from at least three different determinations. All CA isofoms were recombinant ones obtained in-house.

[0152] Calculation of C log P.

[0153] C log P was calculated by means of ChemDraw-Ultra Software 8.

Results

[0154] Chemistry

[0155] The general synthesis of the carbamates designed in the current study is presented in Scheme 1 and Scheme 2. Compounds (1)-(10) shown in FIG. 1, as well as compounds of Formula (I) were obtained with isolated yields ranging between 62-85%.

[0156] Pharmacology

[0157] The anticonvulsant activity profile of compounds 1-10 was determined using the MES test, which measures seizure spread, scMet test, which measures seizure threshold and the 6 Hz (32 mA) psychomotor test. These tests are mechanism-independent animal seizure models that enable identification of compounds preventing seizure spread [27]. Compounds 1-10 were administered i.p. to mice and orally (or i.p.) to rats at fixed doses of 30, 100 or 300 mg/kg, and the anticonvulsant protection was observed at different times after dosing. The method applied here allowed the determination of the number of animals (in a group consisting of 4 or 8 mice or rats) protected against electrically- or chemically-induced seizures as well as the estimation of the time course of anticonvulsant activity together with time of peak effect (TPE).

[0158] Table 1 presents the anticonvulsant activity and neurotoxicity or minimal behavioral impairment of all tested compounds (compounds 1-10) at the mouse-MES and mouse-6 Hz (32 mA) tests (i.p.). At the MES model, these three most active compounds (compounds 1, 9 and 10) showed some protection at 30 mg/kg and full or almost full (compound 1) protection at 100 mg/kg with no signs of neurotoxicity. These compounds showed partial protection with no neurotoxicity at doses of 30 and 100 mg/kg and full or almost full (compound 1) protection 300 mg/kg at the 6 Hz test with no neurotoxicity.

TABLE-US-00001 TABLE 1 Anticonvulsant activity and neurotoxicity (minimal behavioral impairment) of 4-sulfonamidobenzene carbamates administered i.p. to mice. Dose MES.sup.a 6 Hz.sup.a, b Tox.sup.c Cmpd (mg/kg) 0.5 h.sup.d 2.0 h 0.5 h 2.0 h 0.5 h 2.0 h 1 30 0/4 0/4 1/4 0/4 0/8 0/8 100 0/4 3/4 1/4 1/4 0/8 0/8 300 0/4 4/4 0/4 3/4 0/8 0/8 2 30 0/4 0/4 0/4 0/4 0/8 0/8 100 1/4 0/4 3/4 0/4 0/8 0/8 300 1/4 1/4 2/4 1/4 0/8 0/8 3 30 0/4 0/4 0/4 0/4 0/8 0/8 100 0/4 0/4 0/4 0/4 0/8 0/8 300 0/4 0/4 1/4 0/4 0/8 0/8 4 30 0/4 0/4 0/4 0/4 0/8 0/8 100 0/4 0/4 0/4 0/4 0/8 0/8 300 1/4 1/4 0/4 0/4 0/8 0/8 5 30 0/4 1/4 0/4 0/4 0/8 0/8 100 0/4 1/4 0/4 0/4 0/8 0/8 300 0/4 2/4 0/4 0/4 0/8 0/8 6 30 0/4 0/4 0/4 0/4 0/8 0/8 100 0/4 0/4 1/4 0/4 0/8 0/8 300 0/4 0/4 1/4 1/4 0/8 0/8 7 30 0/4 0/4 1/4 0/4 0/8 0/8 100 0/4 1/4 1/4 2/4 0/8 0/8 300 0/4 2/4 4/4 3/4 0/8 0/8 8 30 0/4 2/4 0/4 0/4 0/8 0/8 100 0/4 4/4 0/4 0/4 0/8 0/8 300 1/4 4/4 2/4 1/4 1/8 0/8 9 30 3/4 0/4 2/4 0/4 0/8 0/8 100 3/4 4/4 2/4 0/4 0/8 0/8 300 4/4 4/4 4/4 1/4 0/8 0/8 10 30 3/4 1/4 1/4 0/4 1/8 0/8 100 4/4 4/4 3/4 2/4 0/8 0/8 300 3/4 4/4 4/4 4/4 1/8 0/8 .sup.aData indicate number of mice protected/number of mice tested. The animals were examined at two pretreatment times: 0.5 and 2 h. .sup.bThe 6 Hz psychomotor test was conducted with 32 mA. Maximal electroshock (MES) test (number of animals protected/number of animals tested Neurotoxicity was evaluated as motor impairment or sedation (number of animals affected/number of animals tested). Time after drug administration.

[0159] Comparative quantitative evaluation at the mouse-MES, scMet and 6 Hz (32 mA) (i.p.) models showed that compounds 1, 9 and 10 demonstrated anticonvulsant activity in the mouse-MES and 6 Hz models with ED.sub.50 values of 136, 31 and 14 mg/kg (MES) and 75 mg/kg, 53 mg/kg and 80 mg/g (6 Hz-32 mA), respectively (Table 2). At the scMet test, compound 10 had an ED.sub.50 value of 70 mg/kg however, compounds 1 and 9 had a relatively high ED.sub.50 values. Compound 10 had also an ED.sub.50 value of 59 mg/kg at the corneal kindled mouse model.

[0160] Following oral administration to rats compounds 1, 9 10 had MES-ED.sub.50 value of 36 mg/kg, 23 mg/kg, and 28 mg/kg, respectively but were inactive at scMet model. Following i.p. administration to rats compound 10 had an MES-ED.sub.50 value of 13 mg/kg, showing similar MES-ED.sub.50 values after oral and i.p. administration to rats. At the rat-MES test, compounds 9 and 10 had a wide protective index (PI>19) (Table 3).

TABLE-US-00002 TABLE 2 Quantitative anticonvulsant data (ED.sub.50, TD.sub.50 and PI values) in mice dosed i.p..sup.a MES-ED.sub.50 scMet-ED.sub.50 6 Hz-ED.sub.50 CKM - ED.sub.50 Neurox-TD.sub.50 (mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg) Cmpd [95%CI].sup.a PI.sup.b [95%CI].sup.a PI.sup.b [95%CI].sup.a I.sup.b [95%CI].sup.a PI.sup.b [95%CI] 1 136 >3.6 >300 >1.6 .sup.d74 >6.8 NA >500 [89-212] [38-125] 9 31 >19.4 369 >1.6 53.sup.d >11.3 NA >600 [20-45] [250-527] [23-94] 10 14 50 70 10 80e 7.9 59 11.8 698 [10-21] [46-99] [50-127] [36 -87] [457-1678] .sup.aMedian Effective (ED.sub.50) and Toxic (TD.sub.50) values. In squared parentheses are the 95% confidence intervals (95% CI) determined by probit analysis.. .sup.c Protective Index (PI = TD.sub.50/ED.sub.50). .sup.dThe 6 Hz test as done at 32 mA. eAt the 6 Hz (44 mA)-ED.sub.50 = 88 mg/kg [62-135 mg/kg].

TABLE-US-00003 TABLE 3 Quantitative anticonvulsant data (ED.sub.50, TD.sub.50 and PI values) in rats dosed p.o or i.p. MES- scMet Neurotoxicity- ED.sub.50 ED.sub.50 TD.sub.50 (mg/kg) (mg/kg) (mg/kg) Compound [95% CI].sup.a PI.sup.b [95% CI].sup.a PIb [95% CI] 1 (p.o.) 36 NA NA NA NA [25-52] 9 (p.o.) 23 >21.4 >250 NA >500 [18-31] 10 (p.o.) 28 >17.8 >250 NA >500 [18-35] 10 (i.p.) 13 >19.2 NA NA >250 [8-22] .sup.aMedian Effective (ED.sub.50) and Toxic (TD.sub.50) values. In squared parentheses are the 95% confidence intervals (95% CI) determined by probit analysis. .sup.cProtective Index (PI = TD.sub.50/ED.sub.50).

[0161] The optimal balance between lipophilic and hydrophilic moieties (log P) is a very important consideration in designing AEDs. The log P values of the synthesized carbamates are depicted in Table 4.

TABLE-US-00004 TABLE 4 Lipophilicity data (Clog P) of the Investigated Compounds. Compound Clog P 1 4.0 2 3.6 3 3.6 4 2.4 5 2.1 6 2.6 7 3.4 8 3.4 9 2.3 10 2.6 .sup.aClog P was calculated by utilizing the ChemDraw Ultra software, version 12

[0162] Teratogenicity

[0163] The teratogenicity profile of the active compounds (1, 9 and 10) is presented in Table 5.

[0164] These compounds showed some indication of teratogenicity when tested at the 1.8 mmol/kg dose but lacked a teratogenic potential at 0.9 mmol/kg. The 0.9 dosage is 4-10 times higher than their mouse-ED.sub.50 values (except for compound 1 mouse-MES-ED.sub.50 value) and 12-20 times higher than their rat-MES-ED.sub.50 values. The active compounds were embryotoxic as evidenced by the high resorption rate but again at doses significantly higher than their anticonvulsant ED.sub.50 values.

TABLE-US-00005 TABLE 5 Teratogenic effect in the SWV mouse model of the test compounds Dose mg/kg No. of No. of No. of No. of live No. of fetuses Fetal weight Comp (mmol/kg) litters implants resorptions fetuses with NTDs mean SD Control 25% CEL 11 142 8 (5.6) 134 (94.4) 0 0.95 0.06 1 616 (1.8) 9 109 59 (54.1)* 50 (45.9) 7 (14.0)* 0.88 0.06* 1 308 (0.9) 10 126 32 (25.4)* 94 (74.6) 1 (1.1) 0.88 0.03* 9 541 (1.8) 9 107 58 (54.2)* 49 (45.8) 9 (18.4)* 0.89 0.08 9 270 (0.9) 10 126 17 (13.5)* 109 (86.5) 3 (2.8) 0.90 0.07 10 541 (1.8) 9 108 52 (48.2)* 56 (51.9) 17 (30.4)* 0.87 0.08* 10 270 (0.9) 11 145 29 (20.0)* 116 (80.0) 9 (7.8)* 0.88 0.03* *significantly different when compared to the control group For statistical purposes either ANOVA with Tukey post-test multiple comparison (Fetus weight) or Contingency Table Analysis with Fisher's exact test (number of resorptions and NTDs) were performed. P value was set at 0.05

[0165] Carbonic Anhydrase (CA) Inhibition

[0166] Table 6 shows the inhibition constant (Ki) of compounds 1-10 against four human carbonic anyhydrase (hCA) isoforms. The compounds' potency varied from the low nanomolar to micromolar, depending on the substitution pattern of the aliphatic chain of the carbamates.

TABLE-US-00006 TABLE 6 Inhibition data of human CA isoforms hCA I, II, IV and VII of compounds 1-10 and compared to the standard sulfonamide inhibitor acetazolamide (AAZ) utilizing a stopped flow CO.sub.2 hydrase assay. K.sub.1 (nM) Compound hCAI hCA II hCA IV hCA VII 1 89.0 5.7 >10000 865.1 2 421.2 8.7 >10000 >10000 3 484.7 19.6 >10000 >10000 4 59.5 4.5 1836.3 44.4 5 5.9 0.6 302.9 24.5 6 169.5 5.2 1690.8 52.0 7 83.5 5.0 2756.6 712.3 8 21.0 3.7 452.4 35.4 9 72.9 5.4 182.6 35.5 10 77.0 7.6 750.0 350.6 AAZ 250 12 74 2.5 * Mean from 3 different assays, by a stopped flow technique (errors were in the range of 5-10% of the reported values)

[0167] In the present invention, a novel class of 4-aminobenzenesulfonamide-carbamates incorporating phenethyl- or branched alkyls with 6-8 carbon atoms in their side-chain were synthesized and evaluated for anticonvulsant activity, teratogenicity and CA inhibition.

[0168] Three of the ten synthesized new carbamates showed anticonvulsant activity at the MES and 6 Hz tests in mice or rats. In mice compounds 1, 9 and 10 had ED.sub.50 values of 236 mg/kg, 31 mg/kg and 14 mg/kg (MES) and 74 mg/, 53 mg/kg and 88 mg/kg (6 Hz), respectively. It worth emphasizing that compound 10 had similar ED.sub.50 at the 6 Hz (32 and 44 mA) tests. Compound 10 had ED.sub.50 values of 13 mg/kg and 59 mg/kg at the rat-MES the mouse corneal kindling tests. Compound 10-PI values was 59 and above >10 mouse and rat MES test, respectively. The aliphatic moiety of compound 1 is an alcoholic congener of sec-butylpropylacetamdie (SPD) a very potent antiepileptic and CNS compound. Compounds 9 and 10 are two constitutional isomers containing, 1,2-dimethybutyl and 3-methylpentyl, respectively in their aliphatic side-chain.

[0169] Comparative analysis of the most active 4-aminobenzenesulfonamide-carbamates designed in this study with the most active 4-aminobenzenesulfonamide amide derivatives synthesized and evaluated in a previous study [18], yields the followings: a) The three most active compounds contained branched butyl or pentyl moieties in their aliphatic side-chain and had similar rat-MES-ED.sub.50 values, ranging from 7.7-23 mg/kg. b) A dimethylbutyl side-chain leads to an active anticonvulsant compound in both the amide and carbamate groups with rat-MES-ED.sub.50 values of 9.4 and 28 mg/kg, respectively. Compound 10-ED.sub.50 and wide PI values were similar those of the best 4-aminobenzenesulfonamide amide derivatives described previously [21]. The log P values of the most active amides ranged between 1.0-1.5 while the log P values of the most active carbamates ranged between 2.3-4, indicating that a higher (more lipophylic) log P value does not lead directly to a more potent anticonvulsant activity. The active branched aliphatic carbamoyl-sulfonamides 1, 9 and 10 had similar log P values as the other less-active compounds. These results imply that BBB (Blood-Brain Barrier) penetration due to lipophilicity is an important factor in affecting the test drugs anticonvulsant efficacy but not the only one.

[0170] These potent carbamates (1, 9 and 10) induced neural tube defects only at doses markedly exceeding their effective dose. None of these compounds were potent inhibitors of carbonic anhydrase IV, but did inhibit isoforms CAs I, II and VII.

[0171] The following SAR can be drawn from the CA inhibition data depicted in Table 6. The isoform CA I was inhibited with potencies ranging between 5.9 and 485 nM by the investigated sulfonamide carbamates, with good inhibition observed for compounds 5 and 8 which incorporate the phenethyl moiety (5, K.sub.I of 5.9 nM) and a highly branched aliphatic chain (8, K.sub.I of 21 nM).

[0172] The carbamates inhibited CA II with K.sub.I values comparable or better to the clinically used standard acetazolamide, with the exception of phenethyl carbamate (5) that was endowed with a Ki value 20 times lower than acetazolamide, (K.sub.I of 0.6 nM). The three compounds that showed in vivo anticonvulsant activity were all highly effective hCA II inhibitors KI values of 5.4-7.6 nM (better than acetazolamide).

[0173] The transmembrane isoform CA IV was not or was poorly inhibited by the designed carbamates. Indeed, only compounds 5, 8 and 9, which respectively incorporate phenethyl moiety, two highly branched aliphatic chains and a short lowly branched chain, were medium potency inhibitors, whereas the remaining ones acted in the micromolar range or did not significantly inhibit the enzyme up to 10000 nM.

[0174] Finally the hCA VII inhibition data (depicted in Table 6) show that inhibitory properties of the investigated carbamates against this CA isoform is deeply related to the degree of branching of the aliphatic chains present in the carbamate functionality. Indeed, whereas the bulky, ramificated chain compounds 2 and 3 did not significantly inhibit the enzyme up to 10000 nM, the remaining ones acted as nanomolar inhibitors of hCA VII with K.sub.Is spanning in a wide nanomolar range (24.5-865 nM) depending on their substitution pattern.

[0175] sec-Butyl (4-sulfamoylphenyl)carbamte (11) is a carbamate derivative of 4-aminobenzenesulfonamide, possessing 4-9 carbons in the aliphatic side chain of the carbamate moieties. sec-Butyl (4-sulfamoylphenyl)carbamate showed a promising anticonvulsant activity in the MES test after ip administration to mice as well as after oral administration to rats with ED.sub.50 values of 75 mg/kg and 25 mg/kg, respectively.