The combination reactions of 3-alkyl-2-cyano-3-methoxyacrylic esters (I) and their 3-hydrazino derivatives (II) in the presence of pyridine in alcohol at room temperature mostly gave chain intermediates, whose cyclizations led to the formation of only 2,7-dialkyl-5-hydroxypyrazolo-[1,5-a]pyrimidine derivatives. On the other hand, the reaction of Ia (3-Me) with the 5-aminopyrazole derivative (IIIa) obtained by the cyclization of IIa (3-Me) gave 7-hydroxy- and 7-aminopyrazolopyrimidine derivatives in alcohol under reflux via an intermediate. The reactions of 2-cyano-3-ethoxycrotononitrile with IIa or IIIa both afforded 7-aminopyrazolopyrimidine derivatives directly.
在室温下,3-烷基-2-
氰基-3-甲氧基
丙烯酸酯(I)与它们的 3-
肼基衍
生物(II)在
吡啶存在下在
乙醇中发生的结合反应大多产生链中间体,其环化反应只导致形成 2,7-二烷基-5-羟基
吡唑并-[1,5-a]
嘧啶衍
生物。另一方面,Ia(3-Me)与 IIa(3-Me)环化得到的 5-
氨基
吡唑衍
生物(IIIa)反应,在醇中通过中间体回流得到 7-羟基和 7-
氨基
吡唑嘧啶衍
生物。2-Cyano-3-ethoxycrotononitrile 与 IIa 或 IIIa 反应均可直接得到 7-
氨基
吡唑嘧啶衍
生物。