Reaction of Cyano Active Methylene Compounds with 2-Hydroxy-1-naphthal-4-acetylaniline: An Unexpected Result

Abstract

Condensation of cyano active methylene compounds (1-5) with 2-hydroxy-1-naphthal-4-acetylaniline, the compound containing both carbon-nitrogen double bond as well as carbon-oxygen double bond, in equimolar ratio resulted in the formation of crude solids (1a-5a) which were crystallized from benzene. The products were characterized as 3-imino-3H-benzo[f]chromene derivatives (1a-5a) on the basis of elemental analysis and spectral studies. Reaction of compounds (1-5) with 2-hydroxy-1-naphthal-4-acetylaniline in 2:1 molar ratio also yielded the same products (1a-5a). Thus, cyano active methylene compounds reacted chemoselectively with carbon-nitrogen double bond of 2-hydroxy-1-naphthal-4-acetylaniline, leaving the carbon-oxygen double bond, considered to be more reactive, intact, leading to the formation of mono addition-elimination products which cyclized due to interaction between hydroxyl group and cyano group.