Convenient synthesis of spiro[indoline-3,4'-pyrano[2,3-c]pyrazole] and spiro[acenaphthyl-3,4'-pyrano[2,3-c]pyrazoles] via fourcomponent reaction

The domino four-component reaction of hydrated hydrazine, dimethyl acetylenedicarboxylate, isatin and malononitrile or ethyl cycanoacetate in ethanol in the presence of triethylamine afforded the polysubstituted spiro[indoline-3,4'-pyrano[2,3-c]pyrazole] derivatives in satisfactory yields. Under similar conditions, the four-component reaction containing acenaphthenequinone also resulted in the spiro[acenaphthyl-3,4'-pyrano[2,3-c]pyrazole] in good yields.