Electrophilic halogenation of hydrazones of CF<sub>3</sub>-ynones. Regioselective synthesis of 4-halo-substituted 3-CF<sub>3</sub>-pyrazoles
作者:Vasiliy M. Muzalevskiy、Valentine G. Nenajdenko
DOI:10.1039/c8ob02247j
日期:——
An efficient approach for the synthesis of 4-halo-3-CF3-pyrazoles was elaborated using the cyclization of hydrazones of CF3-ynones induced by electrophilic halogenation. This method can be used for the regioselective synthesis of 3-CF3-pyrazoles substituted at the 4-position with any halogen (I, Br or Cl). The high (up to quantitative) yields, mild conditions and simplicity of the reaction protocol