Process for producing optically active azetidine-2-carboxylic acid

摘要

The present invention provides an efficient, simple, and commercially advantageous process for producing optically active azetidine-2-carboxylic acid, which is an important material for medicines. The process includes the steps of halogenating an optically active N-protected 4-amino-2-hydroxybutyric acid following inversion of the configuration to produce an optically active N-protected 4-amino-2-halobutyryl halide; hydrolyzing the halide; deprotecting the amino group of the hydrolyzed product to produce an optically active 4-amino-2-halobutyric acid; cyclizing the product in an alkaline aqueous solution; and then protecting the amino group of the cyclized product to produce an optically active N-protected azetidine-2-carboxylic acid. The present invention also provides an optically active N-protected 4-amino-2-halobutyryl halide represented by general formula (2): (wherein P represents a protective group for the primary amino group; * indicates that the carbon atom is asymmetric; and each of X and Y independently represents a halogen atom), which is useful for producing the optically active azetidine-2-carboxylic acid.