| 摘要 |
New heterocyclic carboxylic acids of the general formula (I), <IMAGE> wherein Y<1> and Y<2> 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), <IMAGE> 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), <IMAGE> wherein R, Z, Y<1> and Y<2> are as defined above, is treated with an alkali metal halide, and the resulting compound of the general formula (II), <IMAGE> wherein Z, R, Y<1> and Y<2> are as defined above, is either hydrolysed selectively or separated into its isomers and the trans isomer is then hydrolysed. The resulting compounds of the general formula (I) are valuable intermediates of the synthesis of thienamycin and thienamycin analogues. |
