Abstract
An efficient, facile, and simple route for the preparation of spirooxindole-containing fused 1,4-dihydropyridine derivatives through a one-pot, pseudo five-component condensation reaction of isatin or its derivatives, 1,1-bis(methylthio)-2-nitroethylene, 1,3-dicarbonyl compounds, and two equivalents of ammonia in water is reported. The merits of this method include the use of water as a green solvent, and inexpensive and easily available starting materials and catalyst, the high yield of products, and the straightforward work-up.
Key words
ammonia - fused-ring systems - natural products - spirooxindole - water - multicomponent reactions