Regioselective synthesis of pyrimido[1,2-a][1,3,5]triazin-6-ones via reaction of 1-(6-oxo-1,6-dihydropyrimidin-2-yl)guanidines with triethylorthoacetate: observation of an unexpected rearrangement
作者:Nikhil Sachdeva、Anton V. Dolzhenko、Wai Keung Chui
DOI:10.1039/c2ob25195g
日期:——
A novel thermal rearrangement, involving pyrimidine ring opening and subsequent ring closure leading to recyclization of the system, was identified in the reaction of (6-oxo-1,6-dihydropyrimidin-2-yl)guanidines 3 (where NR1R2 = NH2, NH alkyl, NH aralkyl, NHCH2Ph(R)) with triethyl orthoacetate, affording 4-substituted-2-methyl-6H-pyrimido[1,2-a][1,3,5]triazin-6-ones 6 and their ring opened products
在(6-氧代-1,6-二氢嘧啶-2-基)胍3(其中NR 1 R 2 = NH 2,NH烷基,NH芳烷基,NHCH 2 Ph(R))与原乙酸三乙酯得到4-取代的-2-甲基-6 H-嘧啶基[1,2- a ] [1,3,5]三嗪-6-ones 6及其开环产物。但是,对于带有叔氨基或苯胺基取代基的(6-氧代-1,6-二氢嘧啶-2-基)胍3,未观察到这样的重排(即NR 1 R 2 = N(CH 3)2,吲哚啉,吗啉代,NHAr)。如所预期的,获得2-取代的-4-甲基-6 H-嘧啶基[1,2- a ] [1,3,5]三嗪-6-酮4作为最终产物。进行了实验结构确定和理论研究,以了解所观察到的热重排。此外,尝试使用以下方法获得相似的嘧啶并[1,2- a ] [1,3,5] triazin-6-onesN,N-二甲基乙酰胺二甲基乙缩醛(DMA-DMA)作为一个碳插入合成子,由于与第二个DMA-DMA分子进一