An optimized and sustainable Brønsted acid-catalyzed green synthesis of polyhydroquinoline derivatives

An efficient and sustainable protocol has been developed for the synthesis of polyhydroquinoline derivatives through a one-pot Hantzsch-type multicomponent reaction using pentafluorophenyl-ammonium triflate (PFPAT) as a recyclable Brønsted acid catalyst under solvent-free conditions. Under the optimized reaction conditions (10 mol% PFPAT, 90 °C), a series of polyhydroquinoline derivatives was synthesized in good to excellent yields (72–94%) within short reaction times. The methodology offers operational simplicity, broad substrate compatibility, facile catalyst recovery, and excellent recyclability with minimal loss of catalytic activity. The solvent-free reaction conditions and reusable catalyst make the protocol an environmentally benign and sustainable approach for the synthesis of biologically important polyhydroquinoline derivatives, demonstrating the potential of PFPAT as an efficient catalyst for green organic synthesis.