PROCESS FOR PREPARING 3-ALKYL-3-CEPHEM-4-CARBOXYLIC ACIDS AND INTERMEDIATES THEREOF

摘要

A new process for preparing 3-alkyl-3-cephem-4-carboxylic acids of the general formula: wherein R1 is amino or a substituted amino, R2 is carboxy or a protected carboxy and R3 is a lower alkyl, and NEW INTERMEDIATES OF THE GENERAL FORMULA: wherein R1, R2 and R3 are each as defined above and Y' is a residue of ammonia or a saturated aliphatic amine or a secondary cyclic amine, comprises reacting a compound of the formula wherein X is a residue of a thiol compound, with a condensing agent or a polar solvent, or with ammonia or an amine, respectively. In the latter case, the resultant new intermediate may further be reacted with a condensing agent or a polar solvent to form a 3-alkyl-3-cephem-4-carboxylic acid as above.