Sonochemical multi-component synthesis of spirooxindoles

New and efficient multi-component methods have been developed for the synthesis of spirooxindoles in the presence of a catalytic amount of p-TSA as an inexpensive and available catalyst in EtOH under ultrasound irradiation. The method is simple, starts from readily accessible commercial starting materials, and provides biologically interesting products in good yields and short reaction times.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights► Sonochemical four-component synthesis of spiro[benzofuroquinoline-11,3′-indoline]-tetraone. ► Sonochemical four-component synthesis of 3,3′-(2-oxo-1,2- dihydroacenaphthylene-1,1-diyl)bis(4-hydroxy furan-2(5H)-one). ► Sonochemical Three-component synthesis of spiro[furopyrazolopyridine-4,3′-indoline]-dione. ► Sonochemical three-component synthesis of spiro[benzopyrazoloquinoline-4,3′-indoline]-trione.