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 regioselective synthesis of 4-nitro- or 4-chloro-tetrasubstituted pyrazoles. 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.
我们报告了腙与β-溴-或β-氯-β-硝基苯乙烯的酸催化环加成反应,用于区域选择性合成4-硝基-或4-氯-四取代吡唑。源自常见的 4-卤代-4-硝基吡唑烷中间体,所形成的吡唑产物的特性取决于卤素和硝基取代基的相对离去基团能力。