HETEROCYCLIC CARBOXYLIC ACIDS AND A PROCESS FOR THE PREPARATION THEREOF

摘要

New heterocyclic carbogylic acids of the general formula (I), (I) wherein y1 and y2 form together a removable carbonyl protecting group and R is a removable amido protecting group, are prepared in such a way that a compound of the general formula (IV), ( IV) wherein Z is a C1-5 alkyl group and R is as defined above, is reacted with a compound capable for the temporary protection of the carbonyl group, the resulting compound of the general formula (III), (III) wherein R, Z, y1 and y2 are as defined above, is treated with an alkali metal halide, and the resulting compound of the general formula (II), (II) wherein Z, R, y1 and y2 are as defined above, is either hydrolysed selectively or separated into its isomers and the trans isomers is then hydrolysed. The resulting compounds of the general formula (I) are valuable intermediates of the synthesis of thienamycin and thienamycin analogues.