Method for preparation of beta -lactam compound

摘要

A process for preparing a 7-substituted-3-cephem-4-carboxylic acid of the formula: <IMAGE> or a pharmaceutically acceptable salt thereof, which comprises subjecting a corresponding 7-substituted-3-organic sulfonyloxy-3-cephem-4-carboxylic acid ester of the formula <IMAGE> wherein R is a residue of an organic sulfonic acid, X is esterified carboxy which is an alkoxylcarbonyl, haloalkoxycarbonyl, substituted or unsubstituted aralkoxycarbonyl, benzhydryloxycarbonyl or trityloxycarbonyl, or a pharmaceutically acceptable salt thereof, to hydrogenolysis using a combination of a metal and formic acid as a reducing reagent.