Topic
Benzopyran
About: Benzopyran is a research topic. Over the lifetime, 1889 publications have been published within this topic receiving 15235 citations.
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TL;DR: In this paper, a cyclic ketal is formed by spontaneous dehydration of 2'-hydroxy-warfarin, in which the side-chain phenyl is disposed pseudoaxially and is linked through a 2'-oxygen to the ketal carbon in a fixed cis 1,3-diaxial configuration.
Abstract: A derivative of warfarin, racemic C19H14O4, Mr = 306.32, monoclinic, Cc, a = 9.594 (2), b = 20.437 (4), c = 7.793 (2) A, beta = 109.94 (3) degree, V = 1436.4 (11) A3, Z = 4, Dx = 1.416 g cm-3, lambda(CuK alpha) = 1.5418 A, mu = 7.742 cm-1, F(000) = 640, T = 293 K, final R = 0.053 for 1224 observations. The title molecule, formed by spontaneous dehydration of 2'-hydroxy-warfarin, is a cyclic ketal in which the side-chain phenyl is disposed pseudoaxially and is linked through a 2'-oxygen to the ketal carbon in a fixed cis 1,3-diaxial configuration. Two dihydropyran rings are formed; one fused with the benzopyran ring adopts an e,f-diplanar conformation, the other is a chroman and is in a similar conformation.
TL;DR: In this paper, the development of a novel synthesis of acetophenone benzopyran is reported, which was obtained from 1-(2,4-dihydroxyphenyl)ethanone through O-prenylation and Lewis acids catalyzed intermolecular cyclization reaction.
Abstract: The development of a novel synthesis of acetophenone benzopyran is reported. A acetophenone benzopyran derivative was prepared from 1-(2,4-dihydroxyphenyl)ethanone (3) through O-prenylation and Lewis acids catalyzed intermolecular cyclization reaction. The structure of product 1-(3,4-dihydro-4,4-dimethyl-7-hydroxy-2H-1- benzopyran -6-yl)- ethanone (1) was characterized by UV, IR, 1H-NMR, 13C-NMR and elemental analysis.
01 Jan 2016
TL;DR: In this article, 3-methyl-1H-2-benzopyran-1-one was synthesized in excellent yields by the reaction of homophthalic anhydride with acetyl chloride using pyridine as a catalyst.
Abstract: 3-methyl-1H-2-benzopyran-1-one was synthesized in excellent yields by the reaction of homophthalic anhydride with acetyl chloride using pyridine as a catalyst, followed by rearrangement of 4-acetyl-1H-2-benzopyran-1,3(4H)- dione with Conc. Sulphuric acid at high temperature.