Amino acid derivatives and their production and use in preparing carbapenem and carbapenam compounds
申请人:AJINOMOTO CO., INC.
公开号:EP0259987A2
公开(公告)日:1988-03-16
Novel amino acid derivatives of the formula
wherein R1 is a protecting group removable under reducing or acid conditions, and R2 and R5 are hydrogen or carboxylic protecting groups, are useful as intermediates in preparing stereospecific carbapenam/carbapenem derivatives. R1 is removed under reducing conditions to form a pyrrolidine derivative, which is further cyclised from the R5= H compound to form a β-lactam ring. Stereospecificity at the 6-position is achieved by treatment with lithium di-isopropylamide (LDA) and quenching at different temperatures. Compound (I) can be prepared by treating R1-protected R3-pyrrolidone carboxylic acid R2- ester with a lithium enolate of the formula R4CHLiCO2R5. The lithium enolate can be formed from R4CH2CO2R5 by treatment with LDA.