反应详情

Vilsmeier reagent, which was prepared from N,N-dimethylformamide (0.37 ml) and phosphorus oxychloride (0.44 ml) in a conventional manner, was suspended in dried tetrahydrofuran (20 ml). 2-(tert-Butoxycarbonylmethoxyimino)-2-(6-formamidopyridin-2-yl)acetic acid (syn isomer) (3.0 g) was added thereto under ice-cooling with stirring, and the stirring was continued at the same temperature for an hour to prepare the activated acid solution. This solution was added at a time to a solution of benzhydryl 7-amino-3-vinyl-3-cephem-4-carboxylate (2.72 g) and trimethylsilylacetamide (5.5 g) in methylene chloride at -20° C. with stirring, and the stirring was continued at -20° to -10° C. for an hour. To the reaction mixture were added water (50 ml) and ethyl acetate (200 ml), and the separated organic layer was washed with 5% aqueous sodium bicarbonate and then a saturated aqueous sodium chloride, followed by drying over magnesium sulfate. Removal of the solvent gave benzhydryl 7-[2-(tert-butoxycarbonylmethoxyimino)-2-(6-formamidopyridin-2-yl)acetamido] -3-vinyl-3-cephem-4-carboxylate (syn isomer) (4.8 g), mp 154°-157° C.

1. temperatureunder ice-cooling
2. waitthe stirring was continued at the same temperature for an hour
3. customto prepare the activated acid solution
4. stirringwith stirring
5. waitthe stirring was continued at -20° to -10° C. for an hour
6. washthe separated organic layer was washed with 5% aqueous sodium bicarbonate
7. dry with materialby drying over magnesium sulfate
8. customRemoval of the solvent