Methanol → Benzhydryl 7-amino-3-[2-(2-pyridyl)vinyl]-3-cephem-4-carboxylate

Participants

Reaction Steps

To a suspension of pyridine-phosphorus pentachloride complex prepared from pyridine (48 g) and phosphorus pentachloride (12.7 g) in methylene chloride (120 ml) was added benzhydryl 7-phenylacetamido-3-[2-(2-pyridyl)vinyl]-3-cephem-4-carboxylate (trans isomer) (12 g) under ice-cooling with stirring. The mixture was stirred at the same temperature for 30 minutes and poured into methanol (90 ml) at -25° C. The mixed solution was further stirred at -5° to -15° C. for 10 minutes and then was evaporated under reduced pressure. To the residue was added a mixture of tetrahydrofuran (200 ml), ethyl acetate (200 ml) and water (200 ml) and the mixture was adjusted to pH 6.5 with a saturated aqueous solution of sodium bicarbonate. The separated organic layer was washed with brine, dried over magnesium sulfate and evaporated to give benzhydryl 7-amino-3-[2-(2-pyridyl)vinyl]-3-cephem-4-carboxylate (trans isomer) (6.6 g).

Provenance & Evidence