Synthesis and reactions of some new benzopyranone derivatives with potential biological activities

Abstract

(Chemical Equation Presented) Reaction of visnaginone which derived from the naturally occurring compound "visnagine", with ally! bromide gave O-allyl visnaginone 1, which underwent Claisen rearrangement to yield 7-allylbenzofuran 2 derivative. Vilsmeier Haack formylation of 2 afforded our versatile starting compound furochromene-6-carboxaldehyde (3) which was condensed with cyclohexane-1,3-dione, indandione, malononitrile or ethyl cyanoacetate to yield the ylidene nicotinonitrile and pyridone derivatives 4,7,10a-b. Reaction of 3 with aniline or aniline acting on multiple function X-H (X = NH, O, S) at its ortho position afforded the corresponding anus, imidazolylfurochromene and azepines compounds 11-17. On the other hand, oxidation of visnagin afforded chromene-6-carboxaldehyde derivative 18 which was condensed with different aryl or (heteroaryl) acetonitrile followed by hydrolysis to give pyrano[3,2-g]chromen-4,8-dione derivatives 20a-d and 22.