Process for preparing 7-aminocephalosporins

摘要

7-Aminocephalosporin of the formula: <IMAGE> wherein R2 is 3-oxobutyryloxy group, 1-methyl-1H-tetrazol-5-ylthio group or 1-(2-dimethylaminoethyl)-1H-tetrazol-5-ylthio group, or its salt is prepared by first protecting the carboxyl group at 4-position of the compound of the formula: <IMAGE> wherein R1 is an amino group which may be protected and R2 is the same as defined above, or its salt with an acetyl or propionyl halide, then cleaving the amide group at 7-position of said compound by converting the amide bond to an imino halide, then to an imino ether and subjecting the imino ether to solvolysis.