PROCESS FOR THE CONVERSION OF THE E-ISOMER OF 6-(SUBSTITUTED METHYLENE)-2-PENEMS INTO THE Z-ISOMER

摘要

During the preparation of 6-(substituted methylene)-2-penem compounds (which are known for their antibacterial and beta -lactamase inhibitory properties) mixtures of the E-isomer and the Z-isomer may be formed. The Z-isomer is, however generally preferred, and the present invention provides a process whereby the E-isomer may be converted into the Z-isomer by reaction with an aromatic heterocyclic thiol in the presence of a base.