A novel synthesis of tetra and pentacyclic quinolinopyran tethered pyrazole/coumarin scaffolds via a solid state melt reaction

Abstract

A new protocol has been developed for the efficient synthesis of structurally diverse tetra- and pentacyclic quinolinopyran tethered pyrazole/coumarin architectures via a domino Knoevenagel intramolecular hetero-Diels–Alder (IMHDA) strategy using a solid state melt reaction (SSMR) in a highly diastereo and regioselective fashion. Gratifyingly, these heterocyclic frameworks were synthesized under solvent and catalyst free conditions, without the aid of a work-up and column chromatography purification. The generality and functional tolerance of this convergent and environmentally benign method is very attractive.