Reaction of hydrazones derived from active methylene compounds with Vilsmeier–Haack reagent
作者:Sergey P. Ivonin、Bohdan B. Kurpil’、Oleksandr O. Grygorenko、Dmitry M. Volochnyuk
DOI:10.1007/s00706-014-1293-7
日期:2014.12
ester, nitrile, triphenylphosphonium, and phthalimide moieties were evaluated. It was found that electron-withdrawing and steric effects provided by the substituent at α position strongly influenced the regioselectivity of the reaction. Increasing mesomeric electron-withdrawing effect of this group favors the formation of functionalized 1,3,4-trisubstituted pyrazoles as compared to 1,3-disubstituted