Green one-pot, four-component synthesis of spiro[indoline-3,4'-pyrano[2,3-c]pyrazole] derivatives using amino-functionalized nanoporous silica SBA-15 under solvent-free conditions

Abstract

Propylamine functionalized nanoporous silica (SBA-Pr-NH2) was used as an efficient heterogeneous solid basic nanoreactor in the synthesis of 6'-amino-1'H-spiro[indoline-3,4'-pyrano[2,3-c]pyrazol]-2-one derivatives 5 through a one-pot, four-component condensation of isatin derivatives 1, activated methylene reagents 2, hydrazine hydrate 3 and ß-keto esters 4 under solvent-free conditions at room temperature.