A novel substrate directed multicomponent reaction for the syntheses of tetrahydro-spiro[pyrazolo[4,3-f]quinoline]-8,5'-pyrimidines and tetrahydro-pyrazolo[4,3-f]pyrimido[4,5-b]quinolinesviaselective multiple C-C bond formation under metal-free conditions

Abstract

A versatile and substrate oriented multicomponent reaction for the syntheses of novel highly diastereoselective tetrahydro-1'H-spiro[pyrazolo[4,3-f]quinoline-8,5'-pyrimidine]-2',4',6'(3'H)-triones (d.r. up to 20?:?1 (syn?:?anti)) and tetrahydro-8H-pyrazolo[4,3-f]pyrimido[4,5-b]quinoline-8,10(9H)-dionesviaformation of selective multiple C-C bonds under identical reaction conditions (viz.ethanol as a reaction medium and deep eutectic mixture as a catalyst) is demonstrated. Both approaches involve mild reaction conditions, use of non-hazardous solvents, and facilitate good to excellent reaction yields of the target compounds.