反应详情

40%-Aqueous formaldehyde (24 ml.) and 3%-sodium hydrogen carbonate solution (80 ml.) were added to a solution of [7β-phenoxyacetamido-4-(2,2,2-trichloroethoxycarbonyl) ceph-3-em-3-ylmethyl]-triphenylphosphonium bromide (4.93 g, 6 mmole) in methylene chloride (40 ml.). The two-phase mixture was stirred vigorously for 2 hours and the organic phase was washed with water (100 ml.), dried (MgSO4), and evaporated to an orange foam. This foam was chromatographed on Kieselgel G (Merck; 150 g) with methylene chloride and 0.5%-acetone in methylene chloride as eluants. The appropriate fractions were combined and evaporated to a colourless oil which crystallised on addition of ether. The solvent was removed to give the title ester as a white solid (0.50 g, 17%), m.p. 136° to 140° (decomp), [α]D23 - 33° (c 1.01; Me2SO), λmax. (EtOH), 296 nm (ε 12,100), νmax. (Nujol) 3300 (NH), 1764 (azetidin-2-one), 1716 (CO2R), 1668 and 1509 (CONH) and 920 cm-1 (=CH2), τ (Me2SO-d6) 0.81 (1H, d, J 8 Hz; NH), 2.67 and 2.99 (2H and 3H, 2m; C6H5O), 3.01 (1H, dd, J 11 and 18 Hz; CH=CH2), 4.19 (1H, dd, J 8 and 5 Hz; C7 -H), 4.24 (1H, d, J 18 Hz) and 4.55 (1H, d, 11 Hz) (CH=CH2), 4.71 (1H, d, J 5 Hz; C6 -H), 4.79 and 5.01 (2H, AB-q, J 12 Hz; CH2CCl3), 5.36 (2H, s; C6H5OCH2), 5.98 and 6.34 (2H, AB-q, J 18 Hz; C2 -H2).

1. washthe organic phase was washed with water (100 ml.)
2. dry with materialdried (MgSO4)
3. customevaporated to an orange foam
4. customThis foam was chromatographed on Kieselgel G (Merck; 150 g) with methylene chloride and 0.5%-acetone in methylene chloride as eluants
5. customevaporated to a colourless oil which
6. customcrystallised on addition of ether
7. customThe solvent was removed