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

Reaction of visnaginone which derived from the naturally occurring compound “visnagine”, with allyl 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 anils, 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 .