Process for the preparation of cephalosporin intermediate and its use for the manufacture of cephalosporin compounds

The present invention relates to a method for the preparation of cephalosporin antibiotic of the formula (II), which comprises hydrolyzing and halogenating the ester of formula (III) by photochemical irradiation in one pot using a halogenating agent in the absence or presence of a solvent, to produce compound of formula (I), activating the 4-halogeno-2-substitutedimino-3-oxo-butyric acid of formula (I) using conventional activation agents gives compound of formula (IV), condensing the activated compound of the formula (IV) with 7-amino cephem derivative of the formula (V) to produce a compound of formula (VI), and cyclizing the compound of formula (VI) with thiourea to give cephalosporin compounds of the formula (II).