反应详情

17.3 g of carbonyldiimidazole are initially charged in 200 ml of 1,4-dioxane and, a little at a time, admixed with 20 g of 4-trifluoromethyl-3-pyridinecarboxylic acid. The mixture is stirred at room temperature for 1 h and subsequently heated to 45° C. for 2 h. After cooling to 30° C., 14.5 g of ethoxycarbonylformamide oxime are added and the mixture is stirred at 45° C. for 3 h. The precipitated solid is filtered off with suction and the filtrate is concentrated to 50 ml and, together with the solid, added to 250 ml of ice-water. The solid is filtered off with suction and dried at 50° C. under reduced pressure. This gives 28.7 g of the product as a white solid of mp. 172-174° C.

1. temperaturesubsequently heated to 45° C. for 2 h
2. temperatureAfter cooling to 30° C.
3. stirringthe mixture is stirred at 45° C. for 3 h
4. filtrationThe precipitated solid is filtered off with suction
5. concentrationthe filtrate is concentrated to 50 ml and, together with the solid
6. additionadded to 250 ml of ice-water
7. filtrationThe solid is filtered off with suction
8. customdried at 50° C. under reduced pressure