反应详情

14.4 g (0.05 mol) of dibenzimidazo(1,2a,1',2'-d)tetrahydropyrazine-6,13-dione and 30 g (0.18 mol) of 4-propionylaminoaniline are heated under reflux in 70 ml of dry dimethylformamide for 3 hours. After cooling down, about 700 ml of methanol are added. The precipitated solid is filtered off with suction and washed with methanol and dried to leave 20.7 g of the benzimidazole-2-carboxanilide of the formula ##STR93## Melting point 289°-291° C.

1. temperatureAfter cooling down
2. filtrationThe precipitated solid is filtered off with suction
3. washwashed with methanol
4. customdried