We have achieved a facile synthesis of a combinatorial library of densely substituted pyrazolo[3,4-b]-4,7-dihydropyridines- the mimics of antigenital wart drug podophyllotoxin-from 5-aminopyrazoles and 4-(methylthio) 4H-chromenes. The C(4) pyrazolyl 4H-chromenes, which also possess structural features of podophyllotoxin, were isolable intermediates in the two-step, one-pot condensation. The condensation took place in a one-pot, multicomponent manner when 3-oxo-3-phenylpropanenitriles, hydrazine (precursors for 5-aminopyrazoles) and 4-(methylthio)-4H-chromenes were heated in refluxing ethanol. The condensation, however, stops at 4H-chromene stage when methyl hydrazine or phenylhydrazine were employed. Our findings offer an opportunity for synthesis of a combinatorial library of podophyllotoxin mimics, thus paving the way for discovery of lead candidates for cancer treatment.

中文翻译：

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一锅合成重取代的吡唑并[3,4-b] -4,7-二氢吡啶。

我们已经成功地合成了密集取代的吡唑并[3,4-b] -4,7-二氢吡啶类-抗原性疣药物鬼臼毒素的模拟物，由5-氨基吡唑和4-（甲硫基）4H-色氨酸组成。C（4）吡唑基4H-色酮，也具有鬼臼毒素的结构特征，是两步一锅缩合反应中的可分离中间体。当将3-氧代-3-苯基丙腈，肼（5-氨基吡唑的前体）和4-（甲硫基）-4H-色烯在回流的乙醇中加热时，缩合反应以单锅，多组分的方式进行。然而，当使用甲基肼或苯肼时，缩合在4H-苯甲基阶段停止。我们的发现为鬼臼毒素模拟物的组合文库的合成提供了机会，