Synthesis and biological activities of some fused pyran derivatives

Ethyl benzoylacetate (1) reacted with 2-benzylidenemalanonitrile to afford the corresponding pyrane derivative (2). The latter compound reacted with 2-benzylidenemalanonitrile, carbon disulfide, formamide and benzylidene cyclohexanone, respectively, to afford the corresponding pyrano derivatives (3-6). Compound 2 reacted with ethyl chloroacetate to give compound (8) which cyclized to compound (9) in the presence of sodium ethoxide. Treatment of compound (2) with acetic acid in the presence of sulfuric acid afforded compound (7) which converted to compound (10) when reacted with ethylchloroacetate. Compound (10) reacted with sodium ethoxide to give compound (11). The structure of the newly synthesized compounds has been established on the basis of their analytical and spectral data.