Efficient atom-economic one-pot multicomponent synthesis of benzylpyrazolyl coumarins and novel pyrano[2,3-c]pyrazoles catalysed by 2-aminoethanesulfonic acid (taurine) as a bio-organic catalyst

Abstract

The present work describes eco-friendly multicomponent protocol for the synthesis in excellent yields of structurally diverse benzylpyrazolyl coumarin 5 (a–s) involving the reaction of 4-hydroxycoumarin, ethyl acetoacetate, hydrazine hydrate/phenyl hydrazine hydrate and aldehydes, also novel pyrano[2,3-c]pyrazole derivatives 8 (a–k) integrated by isonicotinic acid hydrazide from reaction of aldehyde, ethyl acetoacetate, malononitrile with isoniazid, employing water as a reaction medium and 2-aminoethanesulfonic acid (taurine) as the catalyst. This new methodology endowed the advantages such as short reaction time, recovery of catalysts after catalytic reaction and reusing them without losing their activity and alleviate of operation.

Graphical Abstract

Keywords:

• 2-Aminoethanesulfonic acid
• benzylpyrazolyl coumarin
• green reaction
• multicomponent reaction
• pyrano[2,3-c]pyrazoles

Acknowledgements

The authors are thankful to Professor Charansingh H. Gill for his invaluable discussions and guidance.

Additional information

Funding

The authors are thankful to Department of Chemistry, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad and this work was supported by Special Assistance Programme SAP, University Grants Commission, New Delhi, India, intended to encourage the pursuit of excellence and teamwork in advanced teaching and research to accelerate the realization of international standards in specific fields.