Processes for making cephems from allenylazetidinone derivatives

摘要

This invention relates to a novel process for making a cephem of formula II from a 2-(3-amino-2-oxo-azetidin-1-yl)-2,3-butadienoate intermediate of formula I using an organo-copper reagent. In another aspect, this invention is concerned with said intermediate. <IMAGE> (A) In the compounds of Scheme (A), R1 is a conventional amino protecting group or an acyl group; R2 is an aromatic heterocyclic or aryl group; R3 is a conventional carboxy protecting group or -CO2R3 taken together forms a physiologically hydrolyzable ester; and R4 is a group selected from the group consisting of C1-6 alkyl, C2-6 alkenyl, C2-6 alkynyl, cyclic C3-6 alkyl, and aryl; and n is 0 or 2.