Methanol → (6R,7R)-Benzhydryl 7-amino-3-((1-methyl-1H-tetrazol-5-ylthio)methyl)-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate

Participants

Reaction Steps

A suspension of phosphorus pentachloride (416 mg) in dry methylene dichloride (10 ml.) was stirred at 23° and a solution of pyridine (0.16 ml.) added. The warm suspension was stirred for 10 minutes, and cooled to 0°, and treated, over 10 minutes, with a solution of diphenylmethyl 3-(1-methyltetrazol-5-ylthiomethyl)-7β-(2-thienylacetamido)-ceph-3-em-4-carboxylate (619 mg) in methylene dichloride (15 ml.). After stirring for a further 45 minutes, during which time the temperature was allowed to rise to 23°, the solution was added, over 5 minutes, to a stirred and cooled (0°) mixture of methanol (5 ml.) and methylene dichloride (15 ml.). The resulting solution was stirred for a further 10 minutes, and washed with N-hydrochloric acid (20 ml.), and stirred for 30 minutes with saturated sodium bicarbonate solution (50 ml.). The organic phase was separated, and washed with saturated aqueous sodium bicarbonate (25 ml.), and treated with some charcoal. The mixture was filtered through a pad of kieselguhr, and the filtrate evaporated to a gum (640 mg.), which was triturated with ether (20 ml) to give the amine as an off-white solid (403 mg, 81.5%), λmax. (CHCl3) 268.5 nm (ε 7,700), νmax. (CHBr3) 3416 and 3350 (NH2), 1780 (β-lactam), and 1720 cm.-1 (CO2R), τ (CDCl3) values include 5.00 and 5.15 (C-6H and C-7 H, two doublets, J 5 Hz.), 6.14 (CH3 -), and 7.59 (NH2).

Provenance & Evidence