| 摘要 |
NEW MATERIAL:A compound shown by formula I [R<1> is organic group reductively eliminable under acidic condition; R<2> and R<5> are H or carboxyl- protecting group; R<3> is alkyl, OH, methoxy or acetoxy; R<4> is ethyl, i-propyl or CH3CR<6>(OR<7>) (R<6> is H or methyl; R<7> is OH-protecting group)]. EXAMPLE:2(S)-Benzyloxycarbonylamino-5-keto-6-t-butyloxycarbonyl-octanoic acid benzyl ester. USE:An intermediate for producing carbapenam or carbapenem such as beta-lactam antibiotics, etc., having excellent antibacterial action. PREPARATION:A lithium enolate of a carboxylic acid ester shown by formula III is added to a pyrrolidonecarboxylic acid ester shown by formula II containing protected amino group and carboxyl group, which is subjected to ring formation to give a compound shown by formula I. |
