Highly efficient KF/Al2O3-catalyzed versatile hetero-Michael addition of nitrogen, oxygen, and sulfur nucleophiles to α,β-ethylenic compounds
作者:Lei Yang、Li-Wen Xu、Chun-Gu Xia
DOI:10.1016/j.tetlet.2005.03.112
日期:2005.5
of KF/Al2O3-catalyzed versatile hetero-Michael addition reaction of nitrogen, oxygen, and sulfur nucleophiles was developed for facile preparation of organic compounds of widely different structures. In contrast with the existing methods using many acidic catalysts, this method is very general, simple, high-yielding, environmentally friendly, and oxygen and moisture tolerant.
开发了KF / Al 2 O 3催化的氮,氧和硫亲核试剂的多功能杂-迈克尔加成反应的第一个实例,可轻松制备结构迥异的有机化合物。与使用许多酸性催化剂的现有方法相比,该方法非常通用,简单,高产率,环境友好并且耐氧气和湿气。
Synthesis of N- and C-azolyl-substituted pyrazolo[1,5-a]pyrimidines by recyclization of pyrimidinium salts
作者:Gevorg G. Danagulyan、Araksya K. Tumanyan、Oganes S. Attaryan、Rafael A. Tamazyan、Anna G. Danagulyan、Armen G. Ayvazyan
DOI:10.1007/s10593-015-1724-3
日期:2015.5
We studied the reaction of 2-(ethoxycarbonyl)methyl-1,4,6-trimethylpyrimidinium iodide with hydrazides of N-azolyl- and D-pyrazolylsubstituted carboxylic acids, which were synthesized by reacting the respective esters with hydrazine hydrate. This reaction was shown to result in recyclization and formation of ethyl 2-(pyrazolylalkyl)- and 2-(azolylalkyl)-5,7-dimethylpyrazolo[1,5-a]pyrimidine-3-carboxylates. Besides pyrazolopyrimidines, the separation of reaction mixture provided in some cases also another recyclization product, 2-hydroxy-5,7-dimethylpyrazolo[1,5-a]pyrimidine.