Process for preparing cephalosporanic acid derivatives

Abstract From the Canadian patent

A process for preparing a cephalosporanic acid derivative or a 7-acylaminocephalosporanic acid derivative which comprises subjecting an esterifying agent to reaction in a liquid sulfur dioxide in the presence of a base with an N-protected-cephalosporin C to obtain a diester, subjecting the diester to reaction in an inert solvent with an iminohalide forming agent to produce an iminohalide, subjecting the iminohalide with a lower alcohol to produce an iminoether, subjecting a product produced after, subjecting the iminoether to reaction with a reactive derivative of an organic acid, to hydrolysis and further eliminating the ester group of the carboxylic acid.