The reaction of 3-(chloromethyl)-7-(phenylacetamido)-3-cephem-4-carboxylic acid 4-methoxybenzyl ester (I) with triphenylphosphine and NaI in acetone gives the corresponding phosphonium salt (II), which is condensed with 4-methylthiazole-5-carboxaldehyde (III) by means of NaHCO3 in dichloromethane affording 3-[2(Z)-(4-methylthiazol-5-yl)vinyl]-7-(phenylacetamido)-3-cephem-4-carboxylic acid 4-methoxybenzyl ester (IV). The cleavage of the amido group of (IV) with PCl5 and pyridine yields the 7-amino compound (V), which is condensed with 2-(methoxyimino)-2-[2-(tritylamino)thiazol-4-yl]acetic acid (VI) by means of POCl3 in dichloromethane giving 3-[2(Z)-(4-methylthiazol-5-yl)vinyl]-7-[2(Z)-methoxyimino)-2-(2-tritylamino)thiazol-4-yl)acetamido]-3-cephem-4-carboxylic acid 4-methoxybenzyl ester (VII). The deprotection of (VII) with trifluoroacetic acid and anisole yields the free amino acid (VIII), which is finally esterified with iodomethyl pivalate (IX) in DMF.