Synthesis of novel symmetrical 2-oxo-spiro[indole-3,4'-pyridines] by a reaction of oxindoles with 1,2-diaza-1,3-dienes.

A simple reaction of some oxindole derivatives with 1,2-diaza-1,3-dienes to produce 2-oxo-spiro[indole-3,4'-pyridines] in good yields is described here. This transformation represents a practical two steps approach to new and biologically interesting 2-oxo-spiro[indole-3,4'-pyridine] scaffolds using a double Michael addition/cyclization sequence.