反应详情

N,N-Dimethylformamide (88 mg) and phosphorus oxychloride (184 mg) were mixed to prepare Vilsmeier reagent in a conventional manner, and the resultant Vilsmeier reagent was suspended in dry tetrahydrofuran (10 ml). To the suspension was added 2-(2-formamidothiazol-4-yl)glyoxylic acid (0.2 g) under ice-cooling with stirring, and the solution was stirred at the same temperature for 30 minutes to prepare the activated acid solution. 4-Nitrobenzyl 7-amino-3-chloro-3-cephem-4-carboxylate (0.4 g) was dissolved in a solution of trimethylsilylacetamide (1.0 g) in ethyl acetate (100 ml). To the solution was added the activated acid solution obtained above all at once at -20° C., and the solution was stirred at -20° to -5° C. for 1.5 hours. After water and ethyl acetate (50 ml) were added to the resultant solution at -20° C., the insoluble substance was separated by filtration, washed with water and acetone in turn and then dried to give 4-nitrobenzyl 7-[2-(2-formamidothiazol-4-yl)glyoxyloylamino]-3-chloro-3-cephem-4-carboxylate (0.1 g).

1. temperaturecooling
2. stirringthe solution was stirred at the same temperature for 30 minutes
3. customto prepare the activated acid solution
4. additionTo the solution was added the activated acid solution
5. customobtained above all at once at -20° C.
6. stirringthe solution was stirred at -20° to -5° C. for 1.5 hours
7. customthe insoluble substance was separated by filtration
8. washwashed with water and acetone in turn
9. customdried