A Collaborative Study: Greener Synthesis of Heterocyclic Compounds Using Rice Husk-Based Catalyst

An efficient, straight forward and sustainable synthetic procedures for the synthesis of few important class of bioactive heterocyclic compounds like dihydro-dichromeno-pyridine-6,8-diones, tetrahydrotetrazolo[5,1-b]quinazolinones and2,4-diaryl hexahydroquinoline-5-ones have been designed using a novel bio-degradable heterogeneous catalyst-sulphonated rice-husk (SRH). The greener catalyst has high porosity and high density of acid groups along with bio-degradable characteristics which has made it different and advantageous material for catalysis as compared to other conventional homogenous solid acid catalyst. We report primarily a new protocol for the synthesis of a group of biologically active compounds such as dihydro-dichromeno-pyridine-6,8-dione, tetrahydrotetrazolo[5,1-b]quinazolinone and2,4-diaryl hexahydroquinoline-5-ones derivatives using sulphonated rice husk (SRH) under greener condition. Operational simplicity, easy recovery of the product, metal free technique and reusability of the catalyst with excellent yield are the important and promising features of this procedure. The prepared solid heterogeneous catalyst was subjected for characterization using different spectroscopic techniques like FTIR, SEM, EDX, Powder XRD before its application for desired reaction.