Amino methyl cephem carboxylic acid

摘要

7-Amino 3-methyl 3-cephem 4-carboxylic acid is made by (a) reaction of penicillin sulphoxide with 2.1-3.5 equiv. trimethylsilyl oxazolidinyl-2-one in inert solvent at 30-80 deg.C; (b) heating the trimethylsilyl cpd. formed at 70-150 deg.C; (c) hydrolysis in acid medium and treatment with 1.1-1.5 equiv. trimethylsilyl oxazolidinyl-2-one in inert solvent, in presence of an organic base at 20-40 deg.C; (d) reaction of the trimethylsilyl ester produced with a phosphorus halide at -40 to 30 deg.C; (e) conversion into an imino-ether by treatment with a 2-5C alcohol; and (f) hydrolysis of the imino-ether in acid medium.