Patent ID: 6313315
Filing Date: 2001-11-06
Classification: C07D

Abstract:
A method for producing an essentially enantiomerically pure N-protected-azetidine-2-carboxylic acid of formula (1): ##STR3##which method comprises:subjecting a crude enantiomerically excess N-protected-azetidine-2-carboxylic acid comprising said enantiomer represented by formula (1) in excess to the other enantiomer thereof to crystallization in an organic solvent selected from aromatic hydrocarbon, aliphatic ether, aliphatic alcohol, aliphatic ketone, aliphatic nitrile, aliphatic amide, aliphatic sulfoxide, aliphatic ester and a mixed solvent thereof,wherein R isan optionally substituted alkyl, alicyclic or alicyclicalkyl group,an optionally substituted alkenyl group,an optionally substituted aryl group,an optionally substituted heteroaryl group, ora dialkylamino group, andabsolute configuration of the asterisked asymmetric carbon atom is S or R.