Reactions of triacetylmethane with monosubstituted hydrazines and amidine analogues. Syntheses of 4-acetyl-3,5-dimethylpyrazole amidinohydrazone and 1,3,5-triazine derivatives
作者:Kaname Takagi、Abdelilah Bajnati、Michel Hubert-Habart
DOI:10.1002/jhet.5570270608
日期:1990.9
Triacetylmethane (1) reacts with amidinohydrazines in acidic medium to afford 4-acetyl-3,5-dimethylpyrazole amidinohydrazone derivatives 2,4. However, a similar reaction of 1 with thiosemicarbazide or semicarbazide led mainly to 3,5-dimethylpyrazole (6). The great propensity of 1 to hydrolysis accounts for this last transformation, as well as for the fact that with guanidine it led to 2-amino-4,6-dimethylpyrimidine
三乙酰甲烷(1)与a肼在酸性介质中反应,得到4-乙酰基3,5-二甲基吡唑a衍生物2,4。然而,1与硫代氨基脲或氨基脲的相似反应主要导致3,5-二甲基吡唑(6)。1的水解趋势很强,这是最后一个转化的原因,也是由于胍导致了2-氨基-4,6-二甲基嘧啶(10)和S-甲基异硫脲提供了出乎意料的2-氨基-的事实。 4-甲基-6-甲硫基1,3,5-三嗪(11)。