Abstract
A new high‐yielding, operationally simple, solvent‐free, and mild method for preparation of pyrazolines, tetrahydrocarbazoles, and indoles has been developed using KHSO4 · H2O impregnated on SiO2. The reactions have been probed under microwave irradiation (MWI), and ultrasonic and thermal conditions, employing different solid supports. The data revealed that KHSO4 · H2O impregnated on SiO2 under MWI provides the best yields in a shorter time under solvent‐free reaction conditions.
Acknowledgments
One of the authors (S.K.) is thankful to C.S.I.R (New Delhi) for a junior research fellowship.