反应详情

Acetic anhydride (8 ml) was added to a solution of 2,2,2-trichloroethyl 7β-amino-3-methylceph-3-em-4-carboxylate (6.91 g, 20 mmole) in 98-100% formic acid (40 ml.), and the orange solution was allowed to stand at room temperature for 35 minutes and then successively evaporated at 30°/15 mm and 30°/1 mm. The orange residue was dissolved in ether (200 ml) and the solution was washed successively with 2N-hydrochloric acid, water and 5% aqueous sodium hydrogen carbonate solution (50 ml of each) and water (100 ml), dried and evaporated to give the title ester as a pale yellow foam (6.50 g, 87%), [α]D + 96° (CHCl3), λmax. 262-263 nm (E1cm1% 152), νmax. (CHBr3) 3400 (NH), 1786 (azetidin-2-one), 1740 (CO2R), and 1700 and 1510 cm-1 (CONH), τ (CDCl3) 1.74 (CHO), 7.79 (C3 -CH3) (Found: Cl, 27.5, 27.2; S, 8.2. C11H11Cl3N2O4S (373.7) requires Cl, 28.5; S, 8.6%).

1. customsuccessively evaporated at 30°/15 mm and 30°/1 mm
2. dissolutionThe orange residue was dissolved in ether (200 ml)
3. washthe solution was washed successively with 2N-hydrochloric acid, water and 5% aqueous sodium hydrogen carbonate solution (50 ml of each) and water (100 ml)
4. customdried
5. customevaporated