A new method for the synthesis of quinazolines based on the annulation of the benzene ring to 5-acetyl-6 methylpyrimidin-2-one(thione) derivatives has been proposed. Condensation of the latter at the methyl group with dimethylformamide dimethyl acetal in boiling PhH leads to the formation of 5-acetyl-6-[2-(dimethylamino)vinyl]pyrimidin-2-ones(thiones), which, when boiled with MeONa in MeOH, cyclize to 5-hydroxyquinazolin-2-ones(thiones). Similarly, 5-acetyl-6-methyl-4-(trifluoromethyl)pyrimidine was converted to 5-hydroxy-4-(trifluoromethyl)quinazoline. Quinazolines are not formed from 5-acetyl-6-methylpyrimidines condensed with dimethylformamide dimethyl acetal at the acetyl group, but 5-acetyl-6-methylpyrimidines can be used to obtain pyrido[2,3-d] pyrimidine derivatives.

提出了一种基于苯环环化为 5-乙酰基-6 甲基嘧啶-2-酮（硫酮）衍生物合成喹唑啉的新方法。后者在沸腾的 PhH 中与二甲基甲酰胺二甲基缩醛在甲基上的缩合导致形成 5-乙酰基-6-[2-（二甲氨基）乙烯基]嘧啶-2-酮（硫酮），当与 MeONa 一起煮沸时， MeOH，环化为 5-羟基喹唑啉-2-酮（硫酮）。类似地，5-乙酰基-6-甲基-4-(三氟甲基)嘧啶转化为5-羟基-4-(三氟甲基)喹唑啉。喹唑啉不是由 5-乙酰基-6-甲基嘧啶与二甲基甲酰胺二甲基缩醛在乙酰基上缩合而成，但 5-乙酰基-6-甲基嘧啶可用于获得吡啶并[2,3- d ]嘧啶衍生物。