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]quinolines via selective multiple C–C bond formation under metal-free conditions

摘要

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-8 H -pyrazolo[4,3- f ]pyrimido[4,5- b ]quinoline-8,10(9 H )-diones via formation 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.