Intermediates for synthesis of cephalosporins and process for preparation of such intermediates

Abstract

A novel 4-halo-2-oxyimino-3-oxo butyric acid-N,N-dimethyl formiminium chloride chlorosulfate of formula (I) useful in the preparation of cephalosporin antibiotics wherein X is chlorine or bromine; R is hydrogen, Calkyl group, an easily removable hydroxyl protective group, —CHCOOR, or —C(CH)COOR, wherein Ris hydrogen or an easily hydrolysable ester group. The compound of formula (I) is prepared by reacting 4-halo-2-oxyimino-3-oxobutyric acid of formula (IV), wherein X, R and Rare as defined above, with N,N-dimethylformiminium chloride chlorosulphate of formula (VII) in an organic solvent at a temperature ranging from −30° C. to −15° C. The cephalosporins that may be prepared from the intermediate include cefdinir, cefditoren pivoxil, cefepime, cefetamet pivoxil, cefixime, cefmenoxime, cefodizime, cefoselis, cefotaxime, cefpirome, cefpodoxime proxetil, cefquinome, ceftazidime, cefteram pivoxil, ceftiofur, ceftizoxime, ceftriaxone and cefuzonam.