Methanol → Diphenylmethyl 7-amino-3-(benzoxazol-2-yl)thio-3-cephem-4-carboxylate

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Reaction Conditions

Reaction Steps

A 327 mg portion of diphenylmethyl 7-phenylacetamido-3-(benzoxazol-2-yl)thio-3-cephem-4-carboxylate was dissolved in 4 ml of methylene chloride and the resulting solution was cooled to -15° C. To this were added 96 μl of pyridine and 161 mg of phosphorous pentachloride, followed by 1 hour of stirring at -5° C. Next, the reaction solution was cooled down to -20° C., mixed with 1.3 ml of methanol, and then stirred for 3 hours at -5° C. The resulting solution was mixed with 4 ml of water, stirred for additional 1 hour at the same temperature, and then subjected to liquid phase separation. The organic layer was mixed with 4 ml of water, adjusted to pH 7 with saturated sodium bicarbonate aqueous solution and then subjected to liquid phase separation. After drying the resulting organic layer on anhydrous magnesium sulfate and distilling off the solvent under a reduced pressure, the residue was purified by a column chromatography (20 g silica gel, toluene:ethyl acetate =2:1) to obtain 207 mg of the title compound (yield, 78%).

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