Ring transformations of 6H-cyclopropa(5a,6a)pyrazolo(1,5-a)pyrimidine. II. Reaction of 5a-acetyl-6a-carbethoxy-5a,6a-dihydro-6H-cyclopropa(5a,6a)pyrazolo(1,5-a)pyrimidine-3-carbonitriles with N-methylaniline.
作者:TAKUSHI KURIHARA、TSUTOMU TANI、KEIKO NASU
DOI:10.1248/cpb.29.1548
日期:——
The reaction of 5a-acetyl-6a-carbethoxy-5a, 6a-dihydro-6H-cyclopropa [5a, 6a] pyrazolo [1, 5-a] pyrimidine-3-carbonitrile (1) with N-methylaniline in refluxing benzene for 20 min afforded four ring-transformed products, namely ethyl E- and Z-β-N-methylanilino-6-pyrazolo [1, 5-a] pyrimidineacrylates (8 and 9), N-pyrazolylpyrrole (10) and N-pyrazolylpyridone (11), together with 4, 7-dihydro-7-(N-methylanilino) methylpyrazolo [1, 5-a] pyrimidine (7). However, the reaction of 2 possessing a methyl group at the 5-position of 1 with N-methylaniline in refluxing xylene gave the 5-methyl derivative of 7 (13) and 5-methylpyrazolo [1, 5-a] pyrimidine (14), together with N, N-dimethylaniline. The mechanism of formation of compounds 8, 9, 10, and 11 is discussed.
5a-acetyl-6a-carbethoxy-5a, 6a-dihydro-6H-cyclopropa [5a, 6a] pyrazolo [1, 5-a] pyrimidine-3-carbonitrile (1) 与 N-甲基苯胺在回流苯中反应 20 分钟后,得到四种环状转化产物、即 E-和 Z-β-N-甲基苯胺基-6-吡唑并[1,5-a]嘧啶丙烯酸乙酯(8 和 9)、N-吡唑基吡咯(10)和 N-吡唑基吡啶酮(11),以及 4,7-二氢-7-(N-甲基苯胺基)甲基吡唑并[1,5-a]嘧啶(7)。然而,在 1 的 5 位上具有一个甲基的 2 与 N-甲基苯胺在回流二甲苯中发生反应,得到了 7 的 5-甲基衍生物(13)和 5-甲基吡唑并[1,5-a]嘧啶(14),以及 N,N-二甲基苯胺。本文讨论了化合物 8、9、10 和 11 的形成机理。