An Efficient Synthesis of Annulated Novel Dihydropyridine Derivatives using Zeolite H-BEA and Zeolite BEA-SO3H

Abstract

Modified zeolite (zeolite BEA-SO₃H) was synthesized with intent to improve the surface area and Si/Al ratio by loading chlorosulphonic acid onto zeolite H-BEA. Parent and modified zeolite were characterized by variety of characterization techniques such as, ICP, FT-IR, XRD, TGA, NH₃-TPD,BET surface area, etc. The catalytic applications of parent and modified zeolite H-BEA were demonstrated through the synthesis of novel quinoline and benzoquinoline substituted dihydropyridines (DHPs) via one pot Hantzsch cyclocondensation reaction. This method affords high percentage yield of DHPs (93%) within short reaction times. The effects of catalysts and substituent’s (different quinolines and benzoquinoline carbaldehydes) on the synthesis of DHPs were studied and related reaction mechanism was proposed