The Chemical Behavior of (2E)-3-(4,9-Dimethoxy-5-Oxo-5H-Furo[3,2-g] Chromen-6-yl)Acrylonitrile Towards Some Carbon Nucleophiles

Abstract

Some novel substituted benzofurans and annulated furochromenes were obtained through the treatment of the novel (2E)-3-(4,9-dimethoxy-5-oxo-5H-furo[3,2-g]chromen-6-yl)acrylonitrile (2) by some active carbon nucleophiles such as active methylene ketones and methylene nitriles. Thus, the reaction of acrylonitrile 2 with acetylacetone, ethyl acetoacetate, diethylmalonate, and acetoacetanilide in ethanol containing piperidine produced efficiently the corresponding polyfunctionalized benzonitrile derivatives 3–5 and furochromeno-pyridine 6, respectively. Also, treatment of acrylonitrile 2 with some methylene nitriles such as malononitrile, ethyl cyanoacetate, and malononitrile dimer afforded the annulated furochromene derivatives 7–9. Furthermore, the pyrido[1,2-a] benzimidazole system 10 was furnished via reaction of acrylonitrile 2 with 2-(1 H-benzimidazol-2-yl)acetonitrile. These reactions took place through Michael addition, retro-Michael, and γ-pyrone ring opening followed by different types of recyclization. The chemical structures of the novel products were established on the basis of their spectral data and elemental analysis.

Graphical Abstract

Keywords:

• Benzofuran
• benzonitrile
• carbon nucleophiles
• 6-formylkhellin
• furo[32-g]chromen-6-ylacrylonitrile
• recyclization

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Funding

The authors extend their appreciation to the Deanship of Scientific Research at King Khalid University for funding this work through General Research Project under grant number (R.G.P1./22/40).