反应详情

Vilsmeier reagent was prepared from phosphorus oxychloride (1.2 g) and N,N-dimethylformamide (0.6 g) in ethyl acetate (2.4 ml) in a usual manner. 2-(2-Formamido-5-chlorothiazol-4-yl)-2-tert-butoxycarbonylmethoxyiminoacetic acid (syn isomer) (2.4 g) was added to the stirred suspension of Vilsmeier reagent in dry tetrahydrofuran (24 ml) under ice-cooling and stirred for 20 minutes at same temperature [Solution A]. N-Trimethylsilylacetamide (6.4 g) was added to the stirred suspension of 7-amino-3-(1,3,4-thiadiazol-2-yl)thiomethyl-3-cephem-4-carboxylic acid (2.0 g) in tetrahydrofuran (40 ml), and the mixture was stirred for 30 minutes at 35° to 40° C. To the solution was added the solution [Solution A] at -10° C., and the resulting solution was stirred at same temperature for 30 minutes. Water and ethyl acetate were added to the reaction mixture at -10° C. The organic layer was separated and added to water. The mixture was adjusted to pH 7.5 with a saturated aqueous solution of sodium bicarbonate. The aqueous layer was separated and adjusted to pH 2.0 with 10% aqueous hydrochloric acid, and then extracted with ethyl acetate. The extract was washed with a saturated aqueous solution of sodium chloride, dried over magnesium sulfate and evaporated in vacuo to give 7-[2-(2-formamido-5-chlorothiazol-4-yl)-2-tert-butoxycarbonylmethoxyiminoacetamido]-3-(1,3,4-thiadiazol-2-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) (3.72 g).

1. temperaturecooling
2. stirringthe resulting solution was stirred at same temperature for 30 minutes
3. customThe organic layer was separated
4. additionadded to water
5. customThe aqueous layer was separated
6. extractionextracted with ethyl acetate
7. washThe extract was washed with a saturated aqueous solution of sodium chloride
8. dry with materialdried over magnesium sulfate
9. customevaporated in vacuo