A Quick, Simple and Clean Synthesis of Spiro (indoline-3,4’-pyrazolo[4’,3’:5,6]pyrido[2, 3-d]pyrimidines) in Water through a Novel One-Pot Multicomponent Reaction

摘要

A novel and general protocol for quick, simple and efficient synthesis of spiro[indoline-3,4’-pyrazolo[4’, 3’:5,6]pyrido[2, 3-d] pyrimidines] via one-pot three component reactions of isatins, 5-aminopyrazoles and 6-aminouracils or 2,6-diaminopyrimidin- 4-one in water catalyzed by para-toluene sulfonic acid monohydrate (p-TSA.H2O) under mild reaction conditions has been described. Use of water as the solvent system, application of mild and cost-effective solid p-TSA.H2O as organocatalyst, high yield in short reaction time, simple purification process with no chromatographic technique and operational simplicity make the protocol highly attractive.