Yield:-

Reaction Conditions:

with hydrogenchloride;sodium methylate in methanol;ethyl acetate;

Steps:

4 (4R)-4-Mercapto-2-oxopyrrolidine

PREPARATION 4 (4R)-4-Mercapto-2-oxopyrrolidine 375 mg of (4R)-4-acetylthio-2-oxopyrrolidine [prepared as described in any one of Preparations 1 to 3, above] were dissolved in 5 ml of methanol, and 2.35 ml of a 1N solution of sodium methylate in methanol were then added to the resulting mixture, whilst ice-cooling. The mixture was then stirred for 20 minutes at that temperature. At the end of this time, 2.35 ml of a 1N aqueous solution of hydrogen chloride was added to the reaction mixture, after which the mixture was concentrated to dryness by evaporation under reduced pressure. Ethyl acetate was then added to the residue and any insoluble matter was removed by filtration. The soluble portion in ethyl acetate was then concentrated by evaporation under reduced pressure to give 275 mg of the title compound as crystals, melting at between 69.5° and 70° C. Optical rotation [α]_D²⁴ +36.5° (C=1.18, MeOH). Infrared Absorption Spectrum: (KBr) ν_max cm^-1: 2539, 1699, 1683.

References:

US5424306,1995,A