A Sulfonic Acid Polyvinyl Pyridinium Ionic Liquid Catalyzes the Multi-Component Synthesis of Spiro-indoline-3,5'-pyrano[2,3- d]-pyrimidines and -Pyrazines

Mehdi Khalaj; Mahboubeh Taherkhani; Leo Payen; Axel Klein

doi:10.3390/molecules28093663

A Sulfonic Acid Polyvinyl Pyridinium Ionic Liquid Catalyzes the Multi-Component Synthesis of Spiro-indoline-3,5'-pyrano[2,3- d]-pyrimidines and -Pyrazines

Molecules. 2023 Apr 23;28(9):3663. doi: 10.3390/molecules28093663.

Authors

Mehdi Khalaj¹, Mahboubeh Taherkhani², Leo Payen³, Axel Klein³

Affiliations

¹ Department of Chemistry, Buinzahra Branch, Islamic Azad University, Buinzahra 1477893855, Iran.
² Department of Chemistry, Takestan Branch, Islamic Azad University, Takestan 3481949479, Iran.
³ Institute for Inorganic Chemistry, Department of Chemistry, Faculty of Mathematics and Natural Sciences, University of Cologne, Greinstrasse 6, 50939 Köln, Germany.

Abstract

A sulfonated poly-4-vinyl pyridinium (PVPy-IL-B-SO₃H) containing an acidic pyridinium/HSO₃^- ionic liquid moiety was prepared and used as a catalyst for the three-component reaction of malononitrile with 1-alkylindoline-2,3-diones and 1,3-dimethylpyrimidine-2,4,6(1H,3H,5H)-trione or methyl 5-hydroxy-1H-pyrazole-3-carboxylate, leading to methyl 6'-amino-5'-cyano-2-oxo-2'H-spiro[indoline-3,4'-pyrano[2,3-c]pyrazole]-3'-carboxylates or -3,4'-pyrano[2,3-d]pyrimidine]-6'-carbonitrile derivatives under ultrasonic irradiation conditions. The solid catalyst allows easy separation, is cheap, produces high yields under mild conditions, and does not require column chromatography for product isolation and purification.

Keywords: polymeric ionic liquid; polyvinyl pyridine; spiro-indoline-3,4′-pyrano[2,3-c]pyrazole; spiro-indoline-3,5′-pyrano[2,3-d]pyrimidine; ultrasonic.

Grants and funding

This research received no external funding.