反应详情

A mixture of benzhydryl 7-amino-3-[2-(2-pyridyl)-vinyl]-3-cephem-4-carboxylate (trans isomer) (25 g) and N-(trimethylsilyl)acetamide (4.2 g) in ethyl acetate (20 ml) and tetrahydrofuran (10 ml) was stirred at ambient temperature for 20 minutes to give a clear solution. To the solution was added 2-ethoxyimino-2-(5-amino-1,2,4-thiadiazol-3-yl)-acetylchloride (syn isomer) (1.4 g) at -15°~-20° C. and stirred at the same temperature for 30 minutes. Water (20 ml) was added to the resulting solution, and the separated organic layer was washed with 5% aqueous sodium bicarbonate and brine, dried over magnesium sulfate and evaporated to give benzhydryl 7-[2-ethoxyimino-2-(5-amino-1,2,4-thiadiazol-3-yl)-acetamido]-3-[2-(2-pyridyl)vinyl]-3-cephem-4-carboxylate (syn isomer) (trans isomer) (3.6 g).

1. customto give a clear solution
2. stirringstirred at the same temperature for 30 minutes
3. washthe separated organic layer was washed with 5% aqueous sodium bicarbonate and brine
4. dry with materialdried over magnesium sulfate
5. customevaporated