Abnormally Mild Synthesis of Bis(dithiolo)pyrroles from 2,5-Dimethylpyrroles
摘要:
Treatment of A substituted 2,5-dimethylpyrroles 2 with an equilibrated mixture of disulfur dichloride and DABCO in chloroform at 0 degrees C gives pentathiepinopyrroles 3 in moderate yields; further reaction of 3 with the same mixture at room temperature leads, in an extensive reaction cascade, to bis(dithiolo)pyrroles 4 in high yield; 2 can be converted into 4 in a one-pot operation under unusually mild conditions.
Pyrrole and Pyrazole Ring Closure in Heterogeneous Media
作者:F. Texier-Boullet、B. Klein、J. Hamelin
DOI:10.1055/s-1986-31655
日期:——
Pyrroles and pyrazoles may be conveniently prepared by dispersing primary amines or hydrazines and 1,4- or 1,3-diketones, respectively, on alumina or clay (montmorillonite K 10) without solvent, keeping the mixture at 20°C or higher temperatures for 1-26 h, and then eluting the product with dichloromethane.
One-pot synthesis of N-substituted pyrroles from nitro compounds and 2,5-hexadione over a heterogeneous cobalt catalyst
作者:Zheng Gong、Yu Lei、Peng Zhou、Zehui Zhang
DOI:10.1039/c7nj01898c
日期:——
study, the one-pot heterocyclization of nitro compounds with 2,5-hexadione was studied for the synthesis of N-substituted pyrroles via a Paal–Knorr condensation process. The heterogeneous cobalt–nitrogen catalyst (Co–Nx/C-800-AT) was found to be active for this reaction with formic acid. Formic acid served as a hydrogen donor for the transfer hydrogenation, and also acted as an acidcatalyst. More importantly
在这项研究中,研究了通过Paal–Knorr缩合过程将硝基化合物与2,5-己二酮进行一锅法杂环合成N-取代的吡咯。发现多相钴-氮催化剂(Co-N x / C-800-AT)在与甲酸的该反应中具有活性。甲酸用作转移加氢的氢供体,也用作酸催化剂。更重要的是,该方法对其他官能团具有耐受性,因此以高至优异的产率制备了各种N-取代的吡咯。Co-N x / C-800-AT催化剂非常稳定,可以重复使用几次而不会损失其催化活性。
Hexafluoroisopropanol as solvent and promotor in the Paal-Knorr synthesis of N-substituted diaryl pyrroles
作者:Robert H.E. Schirmacher、Daniel Rösch、Franziska Thomas
DOI:10.1016/j.tet.2021.131985
日期:2021.3
An additive-free synthesis of challenging N-substituted aryl pyrrolesfrom the often poorly soluble corresponding 1,4-diketones by means of the Paal-Knorr pyrrole synthesis is reported, which makes use of the unique properties of 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) as a solvent and reaction promotor. Our procedure offers simple execution and purification as well as easy scale-up and can be applied
The synthesis of N-heteroaromatic compounds via an acceptorless dehydrogenative coupling process involving direct use of ammonia as the nitrogen source was explored. We report the synthesis of pyrazine derivatives from 1,2-diols and the synthesis of N-substituted pyrroles by a multicomponent dehydrogenative coupling of 1,4-diols and primary alcohols with ammonia. The acridine-based Ru-pincer complex
Simple, Efficient and Convenient Synthesis of Pyrroles and Pyrazoles Using Zeolites.
作者:R. Sreekumar∗、Raghavakaimal Padmakumar
DOI:10.1080/00397919808006870
日期:1998.5
Abstract A convenient heterogeneous catalytic methodology for the synthesis of Pyrroles and Pyrazoles by an intermolecular reaction of γ or β-diketones with primary amines or hydrazine derivatives over zeolites are described.