反应详情

Benzyl 6β-aminopenam-3-carboxylate (1.11 g, 4 m mol) in dry dichloromethane (4 ml) with trimethylorthoformate (0.42 g, 0.44 ml, 4 m mol) was treated with 4-nitrobenzaldehyde (0.61 g, 0.4 m mol) in dry methanol (10 ml) at room temperature for 1.5 h. The mixture was then evaporated to dryness, triturated with ethanol and the solid material collected by filtration. Renystallisation from ethanol/ethylacetate gave almost colourless needles (1.2 g 74%); m.p. 95°-96° C.; νmax (CH2Cl2) 1795, 1750, 1530, 1360 cm-1 ; δ(CDCl3) 8.68 (1H, d, J 2 Hz, CH=N), 8.27 and 7.94 (4H, 2d, J 9 Hz), nitrophenyl), 7.38 (5H, s, phenyl), 5.51 (1H, d, J 4 Hz, 5-H), 5.45 (1H, dd, J 2 Hz and 4 Hz, 6-H), 5.23 (2H, s, CH2Ph), 4.93 (1H, t, J 5.5 Hz, 3-H) and 3.45 (2H, d, J 5.5 Hz, 2-H).

1. customThe mixture was then evaporated to dryness
2. customtriturated with ethanol
3. filtrationthe solid material collected by filtration
4. customRenystallisation from ethanol/ethylacetate gave almost colourless needles (1.2 g 74%)