Oxygen analogs of cephalosporins

摘要

In accordance with this invention, it has been found that the oxygen analog of 7-amino-cephalosporanic acid and biologically active derivatives thereof can be formed from esters of 7-amino-cephalosporanic acid. Esters of 7-oxocephalosporanic acid can be formed by diazotization of an ester or 7-amino-cephalosporanic acid and contact of the diazo compound so formed with a hypohalous acid and a base in a water miscible organic solvent. Oxygen analogs of 7-aminocephalosporins isolated as esters are then formed by reducing the aforesaid ester to the corresponding 7 beta -hydroxy-cephalosporanate and then forming the desired analog by introduction of a side chain via hydroxyl group modification. Oxygen analogs of 7-amino-cephalosporins are then formed by regeneration of the acid via protective group removal.