Stereoselective synthesis of 2-hydroxy-4-phenylbutyric acid esters

Abstract

A process is described for the stereospecific preparation of an ester of formula (I): wherein * signifies the (R) stereoisomer; R1 is selected from C1-6 alkyl, preferably ethyl; and R2 is hydrogen, a protecting group or a leaving group which process comprises reaction of a nitrile of formula (II): wherein * signifies the (R) stereoisonomer; and Ph is the phenyl group C6 H5 with a solution of an inorganic acid in an alcohol and optional conversion of the compound of formula (I) wherein R2 is H so prepared to any other desired compound of formula (I) by standard methods in the art. The compounds of formula (I) are chiral esters, useful as intermediates in the synthesis of the family of acetylcholine esterase (ACE) inhibitors known as “prils”, such as lisinopril, cilazapril, enalapril, benazepril, ramipril, delapril, enalaprilat, imidapril, spirapril, trandolapril and others. * Ph-CH2—CH2—CH(OR2)—COOR1  (I) * Ph-CH2—CH2—CH(OH)—CN  (II)

Dependencies are inferred from the claim text.