PROCESS FOR PRODUCING OPTICALLY ACTIVE AZETIDINE-2-CARBOXYLIC ACID

摘要

Preparation of optically active N-protected azetidine-2-carboxylic acid (V) is new. Preparation of optically active N-protected azetidine-2-carboxylic acid of formula (V) comprises: (i) halogenating and inverting the configuration of an optically active N-protected 4-amino-2-hydroxybutyric acid of formula (I) to give an optically active N-protected 4-amino-2-halobutyryl halide of formula (II); (ii) hydrolyzing (II) to give an optically active N-protected 4-amino-2-halobutyric acid of formula (III); (iii) deprotecting (III) and cyclizing in an alkaline aqueous solution to give an azetidine-2-carboxylic acid of formula (IV); and (iv) protecting the imino group of (IV). [Image] Prt : primary amino protecting group; X, Y1>halo; and A : secondary amino protecting group. Independent claims are also included for: (a) steps (i) and (ii) of the process; (b) a process comprising steps (i)-(ii); and (c) compounds of formula (II).