Green synthesis and application of spiro[indoline-3,4'-pyrano[2,3-c]pyrazoles] as selective Hg (II) fluorescence sensor

The expansion of convenient methodologies to simplify the syntheses of bioactive organic compounds such as spirooxindoles is an intense research area in organic synthesis. Spirooxindole derivatives have a distinctive place in organic and medicinal chemistry. In this study, the one-pot synthesis of spiro[indoline- 3,4'-pyrano[2,3-c] pyrazole] derivatives were performed via three-component cyclocondensation reaction of isatins, pyrazolones and malononitrile in aqueous media using SBA-Pr-NHQ, which was prepared by the reaction of SBA-Pr-NCQ with hydrazine hydrate.The advantageous features of this methodology are the mild and neutral reaction media, short reaction times, high yields, and its operational simplicity. The fluorescence emission properties of the product 4i were studied. It has been demonstrated that amino-containing chemical compounds such as product 4i can be used as selective fluorescence chemosensors for the detection of Hg2+.

Automated summary

This study focuses on the one-pot synthesis of spiro[indoline- 3,4'-pyrano[2,3-c] pyrazole] derivatives using isatins, pyrazolones, and malononitrile in aqueous media. The methodology offers mild and neutral reaction conditions, short reaction times, high yields, and operational simplicity.