Formaldehyde → HCID 70615964, compound

Participants

Reaction Steps

A solution of t-butyl 3-bromomethyl-7β-phenoxyacetamidoceph-3-em-4-carboxylate, 1β-oxide (24.97 g, 50.5 mmole) and triphenylphosphine (16.4 g, 1.25 equiv.) in dry methylene chloride (300 ml) was stirred at ca. 20° for 16 hours and then cooled to --20°. A solution of phosphorus tribromide (7.34 ml, 1.5 equiv.) in dry methylene chloride (100 ml) was added with stirring over a period of 30 minutes with the reaction temperature being maintained at -20°; the mixture was then stirred at this temperature for a further hour. 40%-Formaldehyde solution (190 ml) and saturated aqueous sodium hydrogen carbonate solution (750 ml) were added in one portion, and the two-phase mixture was stirred vigorously while its temperature was allowed to reach 20° and then held at this temperature for a further hour. The organic phase was washed with water, dried (MgSO4), and evaporated, and the residue was chromatographed on Kieselgel G (Merck, 0.05 to 0.2 mm, 800 g), eluting with benzene-ethyl acetate (15:1) and (10:1) (2 liters of each). Appropriate fractions were combined and evaporated to give the title ester as a pale-yellow foam (13.53 g, 63%), [α]D - 44° (C 1.00; Me2SO), λmax (EtOH) 292.5 nm (ε 15,300), inflexions at 269.5 and 276.5 nm (ε 10,000 and 12,400), having a p.m.r. spectrum (Me2SO-d6) similar to that described in Example A (iii) 11(a)

Provenance & Evidence