Patent ID: 6127552
Filing Date: 2000-10-03
Classification: C07B,C07C,C07D

Abstract:
A process for producing (R)-3-hydroxy-4-butyrolactone according to the reaction scheme: ##STR3## which comprises the steps of: (1) acylating (S)-3-hydroxy-4-butyrolactone, 1(S), to (S)-3-acyloxy-4-butyrolactone, 2(S), wherein --OR is a leaving group wherein R is a group selected from alkylsulfonyl having 1-12 carbon atoms, arylsulfonyl, formyl and trifluoroacetyl, by reacting 1(S) with an acylating agent selected from an acyl halogenide RY and an anhydride R--O--R wherein Y is halogen, preferably chlorine, and R is as previously defined, optionally in the presence of an organic base consisting of a tertiary amine, in an aprotic organic solvent, at molar ratio 1(S):acylating agent:organic base from 1:1:1 to 1:5:5, or in a basic solvent, at molar ratio 1(S):acylating agent from 1:1 to 1:5, at 10-70.degree. C., for 1-24 hours;(2) hydrolysing 2(S) in an aqueous environment with an acidic resin, for 1-24 hours, thus obtaining (S)-3-acyloxy-4-hydroxybutyric acid, 3(S);(3) converting 3(S) to (R)-3-hydroxymethyl-3-propiolactone 4(R) by treating 3(S) with a base; and(4) converting 4(R) to (R)-3-hydroxy-4-butyrolactone 1(R) in a basic environment and then acidifying to pH 3-0, or directly in an acid environment at pH 3-0, at 10-100.degree. C., for 1-24 hours.