The reaction of 1-chloroethyl chloroformate (I) with cyclohexanol (II) by means of pyridine in dichloromethane gives 1-chloroethyl cyclohexyl carbonate (III), which is converted to the corresponding iodoethyl derivative (IV) with NaI in hot acetonitrile. Finaly this compound is condensed with potassium 7beta-[2-(2-aminothiazol-4-yl)acetamido]-3-[1-[2-(dimethylamino)ethyl]-1H-tetrazol-5-ylthiomethyl]-3-cephem-4-carboxylate (V) in DMF.