反应详情

35.2 g (0.2 mole) of 2-hydrazino-4(3H)-quinazolinone, 500 ml of ethanol and 31.68 g (0.24 mole) of 4,4-dimethoxy-butan-2-one are boiled under reflux for 4.5 hours. The initial suspension has then dissolved. The same volume of 2 N HCl at 50° is added at 50°, whereupon a precipitate soon forms. After warming at 50° for a total of 40 minutes, the 2-(3-methyl-1H-pyrazol-1-yl)-4(3H)-quinazolinone is isolated by filtration with suction. The crude product (35.9 g of melting point 162° to 165° C.) is recrystallized from ethanol and then has a melting point of 165° to 166° C.

1. temperatureunder reflux for 4.5 hours
2. temperatureAfter warming at 50° for a total of 40 minutes