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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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19 citations
TL;DR: The structure was determined by spectroscopic analyses, which included 1D and 2D (1)H and (13)C NMR experiments, as well as MS, IR, and UV spectroscopy, and the reverse reaction was also observed.
Abstract: (Z)-2,2-Dimethyl-8-(3-methyl-2-butenyl)-benzopyran-6-propenoic acid (1) was isolated from Brazilian propolis, together with the known benzopyran derivative, (E)-2, 2-dimethyl-8-(3-methyl-2-butenyl)-benzopyran-6-propenoic acid (2). The structure was determined by spectroscopic analyses, which included 1D and 2D (1)H and (13)C NMR experiments, as well as MS, IR, and UV spectroscopy. Compound 2 rapidly changed to 1 under UV irradiation conditions (365 nm), and the reverse reaction was also observed. The ratio of 1 to 2 reached 2.3 when the reaction began from either 1 or 2, indicating a photostationary state. Compound 1 displayed an approximate 7-fold stronger cytotoxicity against human lung carcinoma cells (HLC-2) compared with 2.
19 citations
TL;DR: The xanthone as mentioned in this paper was derived from the base catalysed self-condensation of the chromone and showed that it can be obtained by refluxing with NaOMe in MeOH.
19 citations
TL;DR: In this article, a rigid analogue of clofibric acid, the active metabolite of the antilipidemic drug clofibrate, has been prepared together with two isomers, 6-chloro-2,3-dihydro-4H-1-benzopyran-3- and 4-carboxylic acids.
Abstract: 6-Chloro-2,3-dihydro-4H-1-benzopyran-2-carboxylic acid, a rigid analogue of clofibric acid, the active metabolite of the antilipidemic drug clofibrate, has been prepared together with two isomers, 6-chloro-2,3-dihydro-4H-1-benzopyran-3- and 4-carboxylic acids. The three acids have been resolved into their optical antipodes and the absolute configuration established by chemical correlation.
19 citations
TL;DR: The features of the oxime-nitrone isomerisation and nitrone-olefin cycloaddition are discussed in this paper, where the features of oxime isomerization are discussed.
Abstract: 4-(Alk-2-enylamino)-2-oxo-2H-1-benzopyran-3-carbaldehyde oximes 5 underwent thermally induced 1,3-dipolar cycloaddition under mild conditions giving isoxazolo[3,4-d][1]benzopyrano[4,3-b]pyridine derivatives 6 in good yields. The features of the oxime–nitrone isomerisation and nitrone–olefin cycloaddition are discussed.
19 citations