Regioselective Synthesis of 4-Nitro- or 4-Chloro-Tetrasubstituted Pyrazoles from Hydrazones and β-Halo-β-nitrostyrenes
作者:Xiaohu Deng、Jimmy T. Liang、Neelakandha S. Mani
DOI:10.1002/ejoc.201301294
日期:2014.1
We report an acid-catalyzed cycloaddition reaction of hydrazones with β-bromo- or β-chloro-β-nitrostyrenes for the regioselectivesynthesis of 4-nitro- or 4-chloro-tetrasubstitutedpyrazoles. Arising from a common 4-halo-4-nitropyrazolidine intermediate, the identity of the pyrazole product formed is dependent on the relative leaving group abilities of the halo and nitro substituents.