反应详情

Vilsmeir reagent was prepared from N,N-dimethylformamide (1.67 ml) and phosphorus oxychloride (1.98 ml) in dry tetrahydrofuran (50.4 ml) in a conventional manner. 2-(p-Nitrobenzyloxycarbonylmethoxyimino)-2-(2-formamidothiazol-4-yl)acetic acid (syn isomer) (7.35 g) was added to the stirred suspension of Vilsmeir reagent under ice-cooling, followed by stirring for 30 minutes at the same temperature. To a solution of 7-amino-3-vinyl-3-cephem-4-carboxylic acid (3.4 g) and trimethylsilylacetamide (11.8 g) in ethyl acetate (35 ml) was added the activated acid solution obtained above at -20° C., and the reaction mixture was stirred at -20° C. to -10° C. for an hour. After water and ethyl acetate were added to the resultant solution, the separated organic layer was washed with water and then dried. A conventional work-up of the solution gave 7-[2-(p-nitrobenzyloxycarbonylmethoxyimino)-2-(2-formamidothiazol-4-yl)acetamido]-3-vinyl-3-cephem-4-carboxylic acid (syn isomer) (6.8 g) as yellowish powder.

1. temperaturecooling
2. customobtained above at -20° C.
3. stirringthe reaction mixture was stirred at -20° C. to -10° C. for an hour
4. washthe separated organic layer was washed with water
5. customdried