吡唑类化合物的研究(Ⅵ)——吡唑[3,4-e]并-1,2,4-三嗪和吡唑[3,4-e]并-1,2,3,4-四嗪衍生物的合成

Studies on Pyrazoles (Ⅵ)——Synthesis of Pyrazolo [3,4-e]-1, 2,4-triazine and Pyrazolo [3,4-e]-1,2,3,4-tetrazine Derivatives

合成了14种1－苯基－3－氨基－5－氧代－4－取代腙吡唑及其关环产物吡唑[3,4-e]并－1，2，4－三嗪和吡唑[3,4-e]并－1，2，3，4－四嗪衍生物，经元素分析，IR^1H NMR和MS确定了其结构，并讨论了一些化合物的IR和1H NMR波谱性质。

Bromination of l-phenyl-3-amino-5-pyrazolone(Ⅰ) in glacial acetic acid gave 1-phenyl-3-amino-4,4-dibromo-5-pyrazolone(Ⅱ). Ⅱ Reacted with a series of substituted hydrazines in hot ethanol to afford l-phenyl-3-amino-5-oxo-4-substituted-hydrazono-pyrazoles( Ⅲa-d). Pyrazolo(3,4-e)-1,2,4-triazine( Ⅳ) was formed by cyclization of 4-ethoxycarbonylhydrazone derivative I ,in 5% NaOMe solution. By coupling I with diazotized aniline or substituted anilines in the presence of pyri-dine, a series of arylhydrazones( Ⅲ) was prepared with a high yield. These compounds were cyclized by diazotization to give the corresponding 2H-2-phenyl-3-oxo-5H-5-arylpyrazolo [3,4-e]-1,2,3,4-tetrazine derivatives( Va-c). Compound Ⅰreacted with nitrous acid to give 1-phenyl-3-amino-4-ni-troso-5-pyrazolone(Ⅵ). Then Ⅵ was treated with thiosemicarbazide in the boiling pyridine to give 1-phenyl-3-amino-5-oxo-4-thiosemicarbazonopyrazole(Ⅶ). Compound Ⅶ was cyclized under a alkaline condition to give pyrazolo[3,4-e]-l,2,4-triazine(Ⅷ).