Gold Modified Zeolite: An Efficient Heterogeneous Catalyst for N-Arylation of Indazole

We herein report N-arylation of indazole with aryl halides using gold modified zeolites (Au-zeolites) as an efficient catalytic system. Au-zeolites with three different gold loading were prepared by ion-exchange method and characterized by UV-visible diffuse reflectance spectroscopy (UV-DRS), transmission electron microscopy and energy-dispersive X-ray spectroscopy (TEM-EDX) and X-ray photoelectron spectroscopy (XPS). The Brunauer-Emmett-Teller (BET) and Langmuir surface areas of the prepared Au(5)-zeolite catalyst were found to be 644 and 929 m(2)g(-1) respectively. Gold-modified zeolites performed as an efficient catalytic system for N-arylation of indazole using diverse aryl halides afforded N1 arylated products in appreciable yield under mild reaction conditions. The catalyst was reusable for at least five times with only a marginal loss of activity. This simple, effective and environmentally benign heterogeneous protocol provides a safer alternative to hazardous, corrosive and more polluting conventional catalysts.