The condensation of 2(Z)-[2-(tert-butoxycarbonylamino)thiazol-4-yl]-2-pentenoic acid (I) with 7-amino-3-(carbamoyloxymethyl)-3-cephem-4-carboxylic acid pivaloylmethyl ester (II) by means of POCl3 and triethylamine (or oxalyl chloride and picoline) gives the corresponding amide (III), which is then deprotected with trifluoroacetic acid and anisole in dichloromethane.