发明授权
US06838567B1 Process for producing optically active azetidine-2-carboxylic acids 失效
光学活性氮杂环丁烷-2-羧酸的制备方法

Process for producing optically active azetidine-2-carboxylic acids
摘要:
An optically active N-protected azetidine-2-carboxylic acid (5) can be produced by preparing an optically active 4-amino-2-halobutyric acid (3) by halogenating an optically active 3-hydroxy-2-pyrrolidinone (1) with inversion of configuration to prepare an optically active 3-halo-2-pyrrolidinone (2) followed by hydrolysis or by halogenating an optically active 4-amino-2-hydroxybutyric acid ester (6) with inversion of configuration to prepare an optically active 4-amino-2-halobutyric acid ester (7) followed by hydrolysis or by halogenating the compound (6) with inversion of configuration to prepare the compound (7), cyclizing the same to prepare the compound (2) followed by hydrolysis, further cyclizing the compound (3) followed by treating the reaction product with an amino group-protecting agent. The thus-obtained compound (5) can be improved its optical purity further by recrystallization
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