Abstract
Background: The indole ring system and 4H-Pyran derivatives are significant components in many drugs and pharmaceutical agents and spirooxindole containing both indole and pyran rings have been shown to possess a wide biological and pharmaceutical properties.
Methods: We synthesized new derivatives of spirooxindole by a three-component reaction of isatin derivatives, malononitrile (or ethyl cyanoacetate) and beta-dicarbonyl compounds in the presence of catalytic amount of N-Phenylpiperazine (NPP) as an organocatalyst.
Results: A series of novel derivatives of spirooxindole with potential biological properties were synthesized by a threecomponent reaction in the presence of catalytic amount of N-Phenylpiperazine (NPP) as an organocatalyst. NPP as an efficient catalyst can be easily handled and removed from the reaction mixture by simple filtration. Compared with the other catalysts, NPP, not only produce equal or better results in terms of reaction time, but also give good to excellent yield of products, thus we introduce it as an efficient catalyst in Knoevenagel condensation and Michael addition reaction.
Conclusion: We have described a novel and efficient catalytic method for the synthesis of spirooxindole derivatives. Mainly, valuable features of this method include the excellent product yields, broader substrate scope, high reaction rates and easy workup procedure, which make it a useful and attractive process for the synthesis of these important compounds.
Keywords: 4H-pyran, isatin, n-phenylpiperazine, organocatalyst, spirooxindole, three-component reaction.
Graphical Abstract