Pyrolysis of suitably functionalized oxadiazoline diesters in refluxing xylenes provided ethyl 1,2-disubstituted 5-hydroxy-6-oxo-1,6-dihydropyrimidine-4-carboxylates in moderate to good yields. Under thermal conditions, the oxadiazoline esters undergo a sequence of complex molecular reorganizations, namely retro-Michael addition, Claisen rearrangement, and cyclization, to produce the desired pyrimidinones.
在回流的二
甲苯中,通过适宜功能化的
1,3,4-噁二唑啉二酯的热解,以中等至良好的产率合成了乙基1,2-二取代的5-羟基-6-氧代-1,6-二氢
嘧啶-4-
羧酸酯。在热条件下,噁二唑啉酯经历一系列复杂的分子重排过程,包括逆迈克尔加成、克莱森重排和环化,从而生成所需的
嘧啶酮。