A series of pyrano[2,3-b]indoles, was efficiently synthesized via one-pot, multi component reaction (MCRs) of 1,3-bifunctional synthon(malononitrile/ethylcyano acetate), aromatic aldehydes and oxiindole in the presence of various basic catalyst. The key advantages of this process are high yields, shorter reaction times, easy work-up, and purification of products by non-chromatographic method.
International Letters of Chemistry, Physics and Astronomy (Volume 26)
H.B. Ghodasara et al., "A Rapid, Convient and Diversified-Multicomponent Synthesis and Characterization of Pyrano[2,3-b]Indoles", International Letters of Chemistry, Physics and Astronomy, Vol. 26, pp. 69-76, 2014