Diverse Directions of Heterocyclizations Involving Derivatives of 5-Aminopyrazoles and N-Arylmaleimides
作者:Sergey Komykhov、Valentin Chebanov、Roman Rudenko、Sergey Desenko、Vladimir Musatov、Oleg Shishkin、Irina Konovalova、Elena Vashchenko
DOI:10.1055/s-0030-1258421
日期:2011.3
Heterocyclization reactions between derivatives of 5-aminopyrazoles and N-arylmaleimides were studied and it was established that several directions are possible. Cyclizations involving 1,3-unsubstituted 5-aminopyrazoles yielded mixtures of two regioisomeric compounds, pyrazolo[1,5-a]pyrimidine-7-carboxamides and pyrazolo[3,4-b]pyridine-4-carboxamides. Reactions of 4-substituted 5-aminopyrazoles in boiling acetic acid or N,N-dimethylformamide in most cases gave pyrazolo[1,5-a]pyrimidine-7-carboxamides as the sole product. The treatment of 1-substituted 5-aminopyrazoles with maleimides possesses high selectivity only in N,N-dimethylformamide yielding pyrazolopyridines while in acetic acid the formation mixtures with pyrrolopyrazolones is observed. The key intermediates of the reaction studied were isolated and discussed.
研究人员对 5-氨基吡唑衍生物和 N-芳基马来酰亚胺之间的异环化反应进行了研究,并确定了几个可能的方向。涉及 1,3- 未取代的 5-氨基吡唑的环化反应产生了两种异构体的混合物,即吡唑并[1,5-a]嘧啶-7-羧酰胺和吡唑并[3,4-b]吡啶-4-羧酰胺。在大多数情况下,4-取代的 5-氨基吡唑在沸腾的乙酸或 N,N-二甲基甲酰胺中反应生成的唯一产物是吡唑并[1,5-a]嘧啶-7-羧酰胺。用马来酰亚胺处理 1-取代的 5-氨基吡唑,只有在 N,N-二甲基甲酰胺中才具有高选择性,生成吡唑并吡啶,而在乙酸中则会与吡咯并吡唑酮形成混合物。对所研究反应的关键中间产物进行了分离和讨论。