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Benzopyrans
About: Benzopyrans is a research topic. Over the lifetime, 694 publications have been published within this topic receiving 8830 citations.
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TL;DR: In this paper, the oxidation of twelve 2-aryl-4H-1-benzopyrans with potassium permanganate in acetone gave the corresponding flavones in excellent yields.
Abstract: The oxidation of twelve 2-aryl-4H-1-benzopyrans with potassium permanganate in acetone gave the corresponding flavones in excellent yields.
TL;DR: In this article, the xanthone was obtained from the base catalysed self-condensation of the chromone by refluxing with NaOMe in MeOH, and the pyran was derived from the reaction of ω-acetyl-2-hydroxyacetophenone with HC(OEt) 3 -Ac 2 O.
Abstract: The xanthone 8 results from the base catalysed self-condensation of the chromone 1 . The chromone 2 gives the xanthones 9 and 11 with sodium and DMF-POCl 3 respectively, phenol 14 with NaOMe, and the pyran 22 with 2-thiomethylchromone 6 . The enamine 16 on Vilsmeier-Haak reaction affords the chloroxanthone 12 . The pyran 15 , isolated as a byproduct from the reaction of ω-acetyl-2-hydroxyacetophenone with HC(OEt) 3 -Ac 2 O, affords the xanthone 13 by refluxing with NaOMe in MeOH.