反应详情

6.0 g of chloro-2-(5-chloro-2-hydroxyphenyl)benz[e][1,3]oxazin-4-one (Example 16), 3.0 ml of triethylamine and 3.3 g of ethyl hydrazinoacetate hydrochloride are boiled under reflux for 2 h in 60 ml of ethanol. On cooling, the product precipitates in crystalline form. It is filtered off and washed with ethanol. After drying, ethyl [3,5-bis(5-chloro-2-hydroxyphenyl)-[1,2,4]triazol-1-yl]acetate is obtained as colorless crystals of m.p. 195-200° C.

1. temperatureOn cooling
2. customthe product precipitates in crystalline form
3. filtrationIt is filtered off
4. washwashed with ethanol
5. customAfter drying