Synthesis of 2,4-diaminopyrrolo[2,3-<i>d</i>]pyrimidines<i>via</i>thermal fischer indolization. Pyrazole formation with ytterbium triflate catalysis
作者:Gordon L. Bundy、Theresa M. Schwartz、John R. Palmer、Lee S. Banitt、William Watt
DOI:10.1002/jhet.5570370611
日期:2000.11
high-yield synthesis of the 2,4-diaminopyrrolo[2,3-d] pyrimidine 4 (PNU-87663) via a Bischler-like alkylation-cyclization sequence was reported earlier. We describe herein an alternative synthesis of this potent antioxidant and several analogs based on the thermal Fischer indolization, starting from hydrazino substituted pyrimidines 5 and 13. In several cases where the thermal Fischer indolization failed
较早地报道了通过类似Bischler的烷基化环化序列的2,4-二氨基吡咯并[2,3- d ]嘧啶4(PNU-87663)的高产率合成。我们在本文中描述了这种有效的抗氧化剂和几种基于热费歇尔吲哚化的类似物的替代合成方法,从肼基取代的嘧啶5和13开始。三氟甲磺酸盐导致了吡唑并[3,4- d ]嘧啶的令人惊讶和前所未有的形成,例如1-甲基-3-苯基-4,6-二-1-吡咯烷基-1 H-吡唑并[3,4- d]嘧啶(24),损失了甲烷元素。此转换的机械细节仍有待研究。