Pot, atom and step economic (PASE) synthesis of medicinally relevant spiro[oxindole 3,4' pyrano[4,3 b]pyran] scaffold
Abstract Fast (3 min) pot, atom and step economics (PASE) potassium fluoride catalyzed multicomponent reaction of isatins, malononitrile and 4 hydroxy 6 methyl 2H pyran 2 one results in efficient formation of substituted spirooxindole 3,4' pyrano[4,3 b]pyrans in 92 96% yields. The developed 'on solvent' approach to the substituted spirooxindole 3,4' pyrano[4,3 b]pyrans the pharmacologically perspective substances with known antiviral, antileishmanial, anticonvulsant and anti HIV activities is beneficial from the viewpoint of diversity oriented large scale processes and represents fast and environmentally benign synthetic concept for the multicomponent reactions strategy.