Procedure to produce an acid derivative 7 - 3 - methyl - beta - amino - CEF - 3 - 4 - carboxylic acid.

摘要

A process for producing a compound of the formula (I) wherein R2 is a hydrogen atom or an ester protective group, which is useful as a precursor for the production of cephalosporin derivatives, comprising reacting a phosphoramide derivative of cephalosporin of the formula (II) wherein R1 is a lower alkyl group and R2 is as defined above, with a phosphorus acid. A further embodiment includes preparing the phosphoramide derivative of cephalosporin of the formula (II) by reactng a compound of the formula (III) wherein R1 and R2 are as defined above, with an acid compound.