Synthesis of [2-(Trimethylsilyl)ethynyl]pyrazoles Based on Bis(trimethylsilyl)acetylene and Arylacetyl Chlorides
作者:Alena S. Pankova、Pavel R. Golubev、Ivan V. Ananyev、Mikhail A. Kuznetsov
DOI:10.1002/ejoc.201200807
日期:2012.10
A practical approach to the synthesis of [2-(trimethylsilyl)ethynyl]pyrazoles was developed through condensation of hydrazines with enynones that are easily accessible frombis(trimethylsilyl)acetylene and arylacetyl chlorides. Optimized conditions for reactions with monoarylhydrazines permit the chemoselective formation of 5-alkynylpyrazoles in high yields (48–94 %). When monoalkylhydrazines or the
一种合成[2-(三甲基甲硅烷基)乙炔基]吡唑的实用方法是通过肼与烯酮缩合而开发的,烯酮很容易从双(三甲基甲硅烷基)乙炔和芳基乙酰氯中获得。与单芳基肼反应的优化条件允许以高产率 (48-94%) 化学选择性地形成 5-炔基吡唑。当使用单烷基肼或母体肼时,3- 和 5- 炔基吡唑的混合物以 73-79% 的产率形成。该方法起始原料价格低廉,适用于多种底物,便于炔基吡唑类化合物的合成。