Chemical intermediates useful to prepare cephalosporins

摘要

7 alpha -Methoxy-7 beta -acylamino cephalosporins are prepared from 7 beta -acylamino cephalosporins through formation of a ketenimine by the action of an acid halide, formation of an addition reaction adduct of this ketenimine, treatment of the adduct with a methoxide to form a 7 alpha -methoxy ketenimine and hydrolysis of the latter ketenimine.