Base-Mediated Reaction of Hydrazones and Nitroolefins with a Reversed Regioselectivity: A Novel Synthesis of 1,3,4-Trisubstituted Pyrazoles
作者:Xiaohu Deng、Neelakandha S. Mani
DOI:10.1021/ol800200j
日期:2008.3.1
A regioselectivesynthesis of 1,3,4-tri- or 1,3,4,5-tetrasubstituted pyrazoles by the reaction of hydrazones with nitroolefins is described. Mediated with strong bases such as t-BuOK, the reaction exhibits a reversed, exclusive 1,3,4-regioselectivity. Subsequent quenching with strong acids such as TFA is essential to achieve good yields. A plausible stepwise cycloaddition reaction mechanism is proposed
Synthesis of 1,3,4-Trisubstituted and 1,3,4,5-Tetrasubstituted Pyrazoles
申请人:Deng Xiaohu
公开号:US20090093637A1
公开(公告)日:2009-04-09
This invention concerns the synthesis of highly substituted pyrazoles, which are structural components of pharmacological compounds, through reaction of hydrazones with nitroolefins.