反应详情

To a mixture of 15 ml of ethylene glycol and 2 ml (0.02 moles) of cc. hydrochloric acid, warmed to 120° C., 2.50 g (0.01 mole) of (2-cyanoimino-5,6-dichloro-1,2,3,4-tetrahydroquinazolin-3-yl) acetonitrile are added, and the solution is stirred at the same temperature for 20 minutes. Then it is cooled to room temperature and made neutral with 10% potassium carbonate solution. The separated crystals are filtered off. Thus 2.72 g (97.1%) of crude 6,7-dichloro-1,5dihydroimidazo[2,1-b]quinazolin-2[3H]-one base are obtained (m.p.>300° C., HPLC content: 97.2%), which is dissolved in a hot mixture of 15 ml of methanol and 16 ml of cc. ethanolic hydrogen chloride (hydrogen chloride content: 0.76 moles/1000 ml) and allowed to crystallize. Then it is cooled, the separated product is filtered off and washed with a slight amount of ethanol.

1. filtrationThe separated crystals are filtered off