Process for producing threo-3-(3,4-dihydroxyphenyl)serine from N-acyl-3,4-dihydroxyphenylalanine amp; 4-carboxy-5-(3,4-dihydroxyphenyl)-oxazoline derivatives

摘要

A process for producing racemic or optically active threo-3-(3,4-dihydroxyphenyl)serine represented by the formula [III]: [wherein * is as defined below] which comprises ```reacting a racemic or optically active N-acyl-3,4-dihydroxyphenylalanine derivative represented by the formula [I]: [wherein R 1 and R 2 independently or together represent a protecting group for a hydroxyl group; R 3 represents a protecting group for a carboxyl group; R 4 represents an optionally substituted alkyl group or an optionally substituted phenyl group; X is a halogen atom; n is 0, 1, 2 or 3; and a carbon marked with the symbol * is an asymmetric carbon] with either a halogen radical generator, or a cerium (IV) salt (in the presence or absence of a copper catalyst), or a persulfate salt in the presence of a copper catalyst to produce a racemic or optically active oxazoline represented by the formula [IV]: [wherein R 1 , R 2 , R 3 , R 4 , X, n and * are as defined above]; and thereafter converting the oxazoline derivative of formula [IV] by known methods into the desired compound of formula [III]. The conversion of the derivative of formula [I] to the oxazoline of formula [IV] is claimed independently. Furthermore, both the oxazoline of formula [IV] and (in part - see claim 22) the derivative of formula [I] are claimed per se.