One pot synthesis of new heterocyclic systems: Polysubstituted pyrano[3,2-c]chromene and benzo[g]chromene derivatives.

A novel library of pyrano[3,2- c ]chromene-3-carbonitrile and benzo[ g ]chromene-3-carbonitrile containing an aroyl or acetyl group moiety at 4-position has been extended by successive three-component reaction of 4-hydroxycoumarin or 2-hydroxy-1,4-naphthoquinone with phenylglyoxal monohydrate and a CH-acid like malononitrile/ethyl cyanoacetate/methyl cyanoacetate/cyanoacetamide under mild condition in ethanol. This approach for the preparation of novel polysubstituted pyrano[3,2- c ]chromene and benzo[ g ]chromene is distinguished with high atom-economy, good to high efficiencies, mild and metal-free conditions, simple workup and easy purification. [ABSTRACT FROM AUTHOR]