Abstract: Described herein is a process for resolving a racemic (C>3) alkyl (R, S) chroman-2-carboxylate compound useful as intermediates in the synthesis of optically pure pharmaceutical compounds is disclosed. The process utilizes a microbial enzyme derived from Serratia marcescens to catalyze the enantioselective hydrolysis of the (C>3) alkyl (S)-chroman-2-carboxylate enantiomer of the racemic mixture to its corresponding carboxylic acid at a faster rate than the R-enantiomer. An enantiomerically pure S-configured carboxylic acid is thereby formed which can undergo acidic esterification to provide an optically pure (C>3) alkyl (S)-chroman-2-carboxylate intermediate for subsequent pharmaceutical synthesis. The nonhydrolyzed (C>3) alkyl (R)-chroman-2-carboxylate enantiomer can also be isolated to provide an optically pure pharmaceutical precursor.

Abstract: A process for resolving racemic alkyl 1,4-benzodioxan-2-carboxylates useful as intermediates in the synthesis of optically pure pharmaceutical compounds such as (S)-doxazosin is disclosed. The process utilizes a microbial enzyme derived from Serratia marcescens to catalyze the enantioselective hydrolysis of the alkyl (S)-1,4-benzodioxan-2-carboxylate enantiomer of the racemic mixture to its corresponding carboxylic acid at a faster rate than the R-enantiomer. An enantiomerically pure S-configured carboxylic acid is thereby formed for subsequent pharmaceutical synthesis. The nonhydrolyzed alkyl (R)-1,4-benzodioxan-2-carboxylate enantiomer can also be isolated and racemized, and the enzymatic hydrolysis reaction repeated.