ethyl 2-methyl-3-sulfanylbutanoate

Conditions: temp:-15.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Under nitrogen atmosphere, a mixture of 40.00 g (0.192 mol) of ethyl 3-acetylthio-2-methylbutyrate and 800 ml of ethanol was cooled to −15° C., 72.01 g (0.212 mol, 1.1 Eq) of a 20% solution of sodium ethoxide in ethanol was added dropwise thereto over 1 hour, and the mixture was stirred for 3 hours. The reaction mixture was neutralized with 15.00 g of acetic acid, and then ethanol was evaporated off under reduced pressure. After addition of an aqueous sodium chloride solution to the residue, extraction with diethyl ether was performed. The organic layer was washed successively with a saturated aqueous sodium bicarbonate solution and brine (twice). The solvent in the organic layer was evaporated off, and vacuum distillation (35 to 36° C./2 torr) was performed to give 17.63 g of the objective compound (GC purity: 99.3%, yield: 56.1%, diastereomer ratio: 80.6/19.4). ethanol was evaporated off under reduced pressure After addition of an aqueous sodium chloride solution to the residue, extraction with diethyl ether The organic layer was washed successively with a saturated aqueous sodium bicarbonate solution and brine (twice) The solvent in the organic layer was evaporated off vacuum distillation (35 to 36° C./2 torr)

Conditions: temp:-15.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Under nitrogen atmosphere, a mixture of 40.00 g (0.192 mol) of ethyl 3-acetylthio-2-methylbutyrate and 800 ml of ethanol was cooled to −15° C., 72.01 g (0.212 mol, 1.1 Eq) of a 20% solution of sodium ethoxide in ethanol was added dropwise thereto over 1 hour, and the mixture was stirred for 3 hours. The reaction mixture was neutralized with 15.00 g of acetic acid, and then ethanol was evaporated off under reduced pressure. After addition of an aqueous sodium chloride solution to the residue, extraction with diethyl ether was performed. The organic layer was washed successively with a saturated aqueous sodium bicarbonate solution and brine (twice). The solvent in the organic layer was evaporated off, and vacuum distillation (35 to 36° C./2 torr) was performed to give 17.63 g of the objective compound (GC purity: 99.3%, yield: 56.1%, diastereomer ratio: 80.6/19.4). ethanol was evaporated off under reduced pressure After addition of an aqueous sodium chloride solution to the residue, extraction with diethyl ether The organic layer was washed successively with a saturated aqueous sodium bicarbonate solution and brine (twice) The solvent in the organic layer was evaporated off vacuum distillation (35 to 36° C./2 torr)

Conditions: temp:-15.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Under nitrogen atmosphere, a mixture of 40.00 g (0.192 mol) of ethyl 3-acetylthio-2-methylbutyrate and 800 ml of ethanol was cooled to −15° C., 72.01 g (0.212 mol, 1.1 Eq) of a 20% solution of sodium ethoxide in ethanol was added dropwise thereto over 1 hour, and the mixture was stirred for 3 hours. The reaction mixture was neutralized with 15.00 g of acetic acid, and then ethanol was evaporated off under reduced pressure. After addition of an aqueous sodium chloride solution to the residue, extraction with diethyl ether was performed. The organic layer was washed successively with a saturated aqueous sodium bicarbonate solution and brine (twice). The solvent in the organic layer was evaporated off, and vacuum distillation (35 to 36° C./2 torr) was performed to give 17.63 g of the objective compound (GC purity: 99.3%, yield: 56.1%, diastereomer ratio: 80.6/19.4). ethanol was evaporated off under reduced pressure After addition of an aqueous sodium chloride solution to the residue, extraction with diethyl ether The organic layer was washed successively with a saturated aqueous sodium bicarbonate solution and brine (twice) The solvent in the organic layer was evaporated off vacuum distillation (35 to 36° C./2 torr)

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

Procedure: The crude product of Example 1 prior to column chromatography (˜9 g) was refluxed with 10 mL ethanol and several drops of 10M HCl (in ethanol) for 12 hours. Distillation (8.5 T, 75° C.) afforded the free thiol as a clear oil (3.7 g, 52%) and as a mixture of stereoisomers. Odor: at 1 ppm in DPG—guava, mango, exotic fruity note, juicy, sweet, tropical and ripe. GC/MS (EI): m/z (%) 162(34), 134(2), 129(34), 89(52), 74(77), 56(100). 1H NMR (CDCl3); δ 4.08-4.17 (m, 2H), 3.14-3.31 (m, 1H), 2.46-2.58 (m, 1H), 1.67 & 1.50 (2d, J=7.79 Hz, 1H mix of diastereomers), 1.17-1.35 (m, 9H)). 13C NMR (CDCl3) for mix of diastereomers: δ 174.6, 60.9, 60.6, 48.8, 47.7, 37.8, 23.6, 21.9, 14.3, 13.5. Distillation (8.5 T, 75° C.)