反应详情

Ethyl 5-[(2,2-dimethyl-4,6-dioxo-1,3-dioxane-5-ylidene)methylamino]1H-pyrazole-4-carboxylate (14.9 g, 45.6 mmol) obtained in step 1 was suspended in methylene chloride (227 mL), and triethylamine (25 mL, 182 mmol) was added. Trimethylsilyl trifluoromethanesulfonate (33.2 mL, 182 mmol) was added dropwise over about 10 min under ice-cooling while maintaining the reaction inside temperature at not more than 10° C., and the mixture was stirred at room temperature for 1 hr. The reaction mixture was cooled to 0° C., and ethanol (75 mL) was added dropwise over 10 min. After the completion of the dropwise addition, the mixture was stirred at room temperature for 10 hr. The precipitated crystals were collected by filtration, washed with cold ethanol (50 mL), and dried under reduced pressure at 40° C. overnight to give the title compound (10.5 g, 91%).

1. temperaturecooling
2. temperaturewhile maintaining
3. customthe reaction inside temperature at not more than 10° C.
4. temperatureThe reaction mixture was cooled to 0° C.
5. additionAfter the completion of the dropwise addition
6. stirringthe mixture was stirred at room temperature for 10 hr
7. filtrationThe precipitated crystals were collected by filtration
8. washwashed with cold ethanol (50 mL)
9. customdried under reduced pressure at 40° C. overnight