Alum (KAl(SO4)2•12H2O) Catalyzed Multicomponent Transformation: Simple, Efficient, and Green Route to Synthesis of Functionalized Spiro[chromeno[2,3-d]pyrimidine-5,3′-indoline]-tetraones in Ionic Liquid Media

The combination of isatin, barbituric acid, and cyclohexane-1,3-dione derivatives in the presence of alum (KAl(SO4)2 center dot 12H2O) as a catalyst for 15 min was found to be a suitable and efficient method for the synthesis of spiro[chromeno[2,3-d]pyrimidine-5,3'-indoline]-tetraones.