α-aminoazoles in synthesis of heterocycles: IV. Regiodirection of 3(5)-amino-5(3)-methylpyrazole reaction with hexafluoroacetylacetone
作者:A. A. Petrov、E. E. Emelina、S. I. Selivanov
DOI:10.1134/s1070428008020139
日期:2008.2
The reaction of 3(5)-amino-5(3)-methylpyrazole with hexafluoroacetylacetone depending on the process conditions led to the formation either of pyrazolo[1,5-a]pyrimidine or pyrazolo[3,4-b]-pyridine. By means of 2D NMR spectroscopy the structure was established of a stable intermediate product, 2-methyl-5,7-bis(trifluoromethyl)-4,5,6,7-tetrahydropyrazolo[1,5-a]-pyrimidine-5,7-diol, whose dehydration yielded the above compounds.
3(5)-氨基-5(3)-甲基吡唑与六氟乙酰乙酮的反应,根据工艺条件的不同,形成了吡唑[1,5-a]嘧啶或吡唑[3,4-b]吡啶。通过二维核磁共振谱学(2D NMR),确定了一个稳定中间产物的结构,2-甲基-5,7-双(三氟甲基)-4,5,6,7-四氢吡唑[1,5-a]嘧啶-5,7-二醇,其脱水反应产生了上述化合物。