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 β-keto esters 4 under solvent-free conditions at room temperature.