120 mg (0.24 mmol) of diphenylmethyl (6R,7R)-7-amino-3-bromomethyl-ceph-3-em-4-carboxylate hydrochloride and 120 mg (0.27 mmol) of (Z)-2-(2-tritylaminothiazol-4-yl)-2-methoxyiminoacetic acid were dissolved in 2.4 ml of methylene chloride, then 98 μl (1.2 mmol) of pyridine and 24 μl (0.27 mmol) of phosphorus oxychloride were added thereto with ice cooling, and reacted for 10 minutes. After the reaction, 12 ml of chloroform was added to the reaction mixture, which was washed with 6 ml of water twice, dried on magnesium sulfate, and the solvent was distilled off. The residue was purified by silica gel chromatography (benzene-ethyl acetate (20:1)) to obtain 190 mg of the title compound.
