Pd-catalyzed direct arylation of phenylpyrazole: Synthesis of fipronil derivatives with aryl boronic acids promoted by a stoichiometric amount of NIS

The palladium-catalyzed direct arylation of phenylpyrazole with aryl boronic acid promoted by a stoichiometric amount of NIS has been reported. Several phenyl pyrazoles, especially for those with trifluoromethyl groups, can participate in the reaction, providing a series of fipronil derivatives of 4-aryl-phenylpyrazole with potential bioactivity in moderate to good yields. All the compounds were characterized by 1H NMR, 13C NMR and HRMS spectroscopic techniques.