Spiro Heterocyclic Compounds. III. Synthesis of Spiro[oxindole-3, 4'-(4'H-pyran)]Compounds

Abstract

Spiro[oxindole-3, 4'-(4'H-pyran)]compounds (IIIa-j), were prepared by the Michael reaction of 3-cyanomethyleneoxindoles (Ia, b) with active methylene compounds. Similarly, the reactions of (Ib, c) with cyclic active methylene compounds, e.g. cyclohexane-1, 3-dione, 3-methyl-1-phenyl-5-pyrazolone and barbituric acid, afforded the corresponding spiro compounds (V-VII) containing the condensed pyran system.