(2S)-2-ethyl-8-methyl-1-thia-4,8-diazaspiro[4.5]decan-3-one

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of AF267B (1.72 gr, 0.008 mol) in water (2.5 ml) was cooled (ice-water bath) and trifluoroacetic acid (3.5 ml) was added. To the cold stirred obtained mixture was added hydrogen peroxide (30%, 0.57 ml, 0.008 mol), the cooling bath was removed and the reaction mixture was stirred at room temperature over night Sodium sulfite was added and the pH of the solution was adjusted to 9 with a saturated solution of sodium carbonate. The aqueous phase was extracted with dichloromethan (2×100 ml) and then with ethyl acetate (1×50 ml). The organic extracts were combined, dried (MgSO4) and the solvent was evaporated. Flash chromatography (silica-gel 60, 230-400 mesh, Merck 1.09385, elution with methanol/chloroform/ammonium hydroxide 10:89:1 v/v) gave AF300. 1H NMR (CDCl3) δ 1.19 (t, j=7.3 Hz, 3H, CH3), 1.85-2.0 (m, 5H), 2.17 (m, 1H), 2.27 (m, 1H), 2.34 (s, 3H, NCH3), 2.6 (m, 2H), 3.30 (dd, j=3.56, 11.13 Hz,: CH3CH2CH), 6.37 (br NH) ppm; MS (EI) m/e 230 (M+). was added obtained mixture the cooling bath was removed the reaction mixture was stirred at room temperature over night Sodium sulfite was added The aqueous phase was extracted with dichloromethan (2×100 ml) dried (MgSO4) the solvent was evaporated Flash chromatography (silica-gel 60, 230-400 mesh, Merck 1.09385, elution with methanol/chloroform/ammonium hydroxide 10:89:1 v/v) gave AF300

Conditions: temp:-10.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a cooled (ice-salt bath) stirred solution of AF267B (6.1 gr, 0.028 mol) in dichloromethane (60 ml) was added m-chloroperbenzoic acid (mCPBA) in small portions over a period of 15 min mCPBA (70%, 7.02 gr, 0.028 mol total). The mixture was stirred for 1 hr and then treated with iron (II) chloride (2.14 ml of 1M solution in water). Stirring and cooling (−10 ° C.) were continued for 1 hr and then stirring continued for 2 hrs at room temperature. Ethylene diamine (1.9 ml, 0.285 mol), sodium hydroxide (30.5 ml of 2N aqueous solution), and petroleum ether 40-60° C. (60 ml) were added. After vigorous shaking the layers were separated, the aqueous layer was extracted with mixture of dichloromethane/petroleum ether 1:1 (600 ml) followed by dichloromethane (first 600 ml then 300 ml). The combined extracts were dried (Na2SO4), filtered and the solvents were removed under reduced pressure. Flash chromatography (silica-gel 60, 230-400 mesh, Merck 1.09385, elution with methanol/chloroform/ammonium hydroxide 10:89:1 v/v) of the residue gave AF292. 1H NMR (CDCl3) δ 1.02 (t, j=7 Hz, 3H), 1.76 1.92 and 2.07 (3xm, 6H), 2.84 (m, 2H), 3.04 (m, 2H), 3.83 (dd, j=8.8, 4 Hz, 1H), 7.66 (NH) ppm; 13C NMR (CDCl3) δ 11.50, 27.24, 42.87, 43.95, 44.10, 48.80, 64.22, 175.22 ppm: MS m/e 200(M+). The compound was >99.9% purity by HPLC, GC. Stirring were continued for 1 hr stirring continued for 2 hrs at room temperature After vigorous shaking the layers were separated the aqueous layer was extracted with mixture of dichloromethane/petroleum ether 1:1 (600 ml) The combined extracts were dried (Na2SO4) filtered the solvents were removed under reduced pressure Flash chromatography (silica-gel 60, 230-400 mesh, Merck 1.09385, elution with methanol/chloroform/ammonium hydroxide 10:89:1 v/v) of the residue gave AF292

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: The obtained (R)-2-mercaptobutyric acid was purified by distillation and then reacted with ammonium acetate and 1-methyl-4-piperidone in boiling cyclohexane. The crude reaction mixture was analyzed by GC on a chiral column and found to contain AF267A accompanied by a small (2-3%) amount of AF267B. The obtained (R)-2-mercaptobutyric acid was purified by distillation reacted with ammonium acetate and 1-methyl-4-piperidone The crude reaction mixture

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: There is also provided in accordance with an embodiment of the invention a process for the preparation of 2-ethyl-8-methyl-1-thia-4,8-diaza-spiro[4.5]decan-3-one (AF267), comprising reacting 4-ethyl piperidone with 2-mercaptobutyric acid and ammonia. In an embodiment of the invention, the process further comprising obtaining the enantiomers AF267A (R-enantiomer) and AF267B (S-enantiomer) by chiral separation. There is also provided in accordance with an embodiment of the invention a process

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of AF267B (1.72 gr, 0.008 mol) in water (2.5 ml) was cooled (ice-water bath) and trifluoroacetic acid (3.5 ml) was added. To the cold stirred obtained mixture was added hydrogen peroxide (30%, 0.57 ml, 0.008 mol), the cooling bath was removed and the reaction mixture was stirred at room temperature over night. Sodium sulfite was added and the pH of the solution was adjusted to 9 with a saturated solution of sodium carbonate. The aqueous phase was extracted with dichloromethan (2×100 ml) and then with ethyl acetate (1×50 ml). The organic extracts were combined, dried (MgSO4) and the solvent was evaporated. Flash chromatography (silica-gel 60, 230–400 mesh, Merck 1.09385, elution with methanol/chloroform/ammonium hydroxide 10:89:1 v/v) gave AF300. 1H NMR (CDCl3) δ 1.19 (t, j=7.3 Hz, 3H, CH3), 1.85–2.0 (m, 5H), 2.17 (m, 1H), 2.27 (m, 1H), 2.34 (s, 3H, NCH3), 2.26 (m, 2H), 3,30 (dd, j=3.56, 11.13 Hz, CH3CH2CH), 6.37 (br NH) ppm; MS (EI) m/e 230 (M+). was added obtained mixture the cooling bath was removed the reaction mixture was stirred at room temperature over night Sodium sulfite was added The aqueous phase was extracted with dichloromethan (2×100 ml) dried (MgSO4) the solvent was evaporated Flash chromatography (silica-gel 60, 230–400 mesh, Merck 1.09385, elution with methanol/chloroform/ammonium hydroxide 10:89:1 v/v) gave AF300

Conditions: temp:-10.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a cooled (ice-salt bath) stirred solution of AF267B (6.1 gr, 0.028 mol) in dichloromethane (60 ml) was added m-chloroperbenzoic acid (mCPBA) in small portions over a period of 15 min mCPBA (70%, 7.02 gr, 0.028 mol total). The mixture was stirred for 1 hr and then treated with iron (II) chloride (2.14 ml of 1M solution in water). Stirring and cooling (−10° C.) were continued for 1 hr and then stirring continued for 2 hrs at room temperature. Ethylene diamine (1.9 ml, 0.285 mol), sodium hydroxide (30.5 ml of 2N aqueous solution), and petroleum ether 40–60° C. (60 ml) were added. After vigorous shaking the layers were separated, the aqueous layer was extracted with mixture of dichloromethane/petroleum ether 1:1 (600 ml) followed by dichloromethane (first 600 ml then 300 ml). The combined extracts were dried (Na2SO4), filtered and the solvents were removed under reduced pressure. Flash chromatography (silica-gel 60, 230–400 mesh, Merck 1.09385, elution with methanol/chloroform/ammonium hydroxide 10:89:1 v/v) of the residue gave AF292. 1H NMR (CDCl3) δ 1.02 (t, j=7 Hz, 3H), 1.76 1.92 and 2.07 (3×m, 6H), 2.84 (m, 2H), 3.04 (m, 2H), 3.83 (dd, j=8.8,4 Hz, 1H), 7.66 (NH) ppm; 13C NMR (CDCl3) δ 11.50, 44.10, 48.80, 64.22, 175.22 ppm: MS m/e 200(M+). The compound was >99.9% purity by HPLC, GC. Stirring were continued for 1 hr stirring continued for 2 hrs at room temperature After vigorous shaking the layers were separated the aqueous layer was extracted with mixture of dichloromethane/petroleum ether 1:1 (600 ml) The combined extracts were dried (Na2SO4) filtered the solvents were removed under reduced pressure Flash chromatography (silica-gel 60, 230–400 mesh, Merck 1.09385, elution with methanol/chloroform/ammonium hydroxide 10:89:1 v/v) of the residue gave AF292

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: The obtained (R)-2-mercaptobutyric acid was purified by distillation and then reacted with ammonium acetate and 1-methyl-4-piperidone in boiling cyclohexane. The crude reaction mixture was analyzed by GC on a chiral column and found to contain AF267A accompanied by a small (2–3%) amount of AF267B. The obtained (R)-2-mercaptobutyric acid was purified by distillation reacted with ammonium acetate and 1-methyl-4-piperidone The crude reaction mixture

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: There is also provided in accordance with an embodiment of the invention a process for the preparation of 2-ethyl-8-methyl-1-thia-4,8-diaza-spiro[4.5]decan-3-one (AF267), comprising reacting 4-ethyl piperidone with 2-mercaptobutyric acid and ammonia. In an embodiment of the invention, the process further comprising obtaining the enantiomers AF267A (R-enantiomer) and AF267B (S-enantiomer) by chiral separation. There is also provided in accordance with an embodiment of the invention a process