Green Aspect for Multicomponent Synthesis of Spiro[4H-indeno[1,2-b]pyridine-4,3-[3H]indoles]

An efficient, four-component reaction of isatin, 1,3-indanedione, ethyl acetoacetate, and ammonium acetate in ethanol/water (9:1) system furnished spiro[4H-indeno[1,2-b]pyridine-4,3-[3H]indoles] at room temperature. Merits of the method are mild reaction conditions, simple workup procedure, and ambient temperature. The synthesized compounds exhibit excellent fluorescence properties.