HCID 21517622, compound → HCID 131710038, compound

Participants

Reaction Steps

4-(4-phenyl-2-oxobutylsulphinyl)-1-(1-t-butoxycarbonyl-1-triphenylphosphoranylidenemethyl)-3-(triphenylmethylamino) azetidin-2-one (200 mg) was refluxed in dry dioxan (5 ml) under nitrogen for 8 hours. The mixture was evaporated to give a foam. The crude foam was chromatographed on silica gel eluting with ethyl acetate/petroleum ether mixtures to give t-butyl 3-β-phenylethyl-7-triphenylmethylamino-3-cephem-4-carboxylate-1-oxide as a yellow solid (87 kg.) μmax (CHCl3) 1785, 1720 cm-1This sulphoxide (87 mg) was dissolved in dimethylformamide (1 ml) and cooled to 0°C. Triphenylphosphine (74 mg) and acetyl chloride (33 mg) were added and the mixture stood at 0°-5°C for 4 hours. The mixture was diluted with ethyl acetate (25 ml) and washed successively with dilute sodium bicarbonate solution and brine. The dried (MgSO4) organic layer was evaporated to give a gum. The gum was chromatographed on silica gel to give the desired cephem (XX111) as a solid foam (77 mg) νmax (CHCl3) 1775 cm-1 (ε-lactam); 1715 cm-1 (ester) δppm (CDCl3) 1.51 (5.9H); 2.4-3.2 (m.7H.1 H exchanges with D2O); 4.19 (d.1H. J=5Hz); 4.5-4.9 (m.1H); 7.0-7.9 (Aromatics).

Provenance & Evidence