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4-Pyrone (γ-pyrone or pyran-4-one) is an unsaturated cyclic chemical compound with the molecular formula C 5 H 4 O 2.It is isomeric with 2-pyrone. Preparation [ edit ]
4H-Pyran was first isolated and characterized in 1962 via pyrolysis of 2-acetoxy-3,4-dihydro-2H-pyran. [1] It was found to be unstable, particularly in the presence of air. 4 H -pyran easily disproportionates to the corresponding dihydropyran and the pyrylium ion, which is easily hydrolyzed in aqueous medium.
Tetrahydropyran (THP) is the organic compound consisting of a saturated six-membered ring containing five carbon atoms and one oxygen atom. It is named by reference to pyran, which contains two double bonds, and may be produced from it by adding four hydrogens. In 2013, its preferred IUPAC name was established as oxane. [1]
It is a derivative of 4-pyrone that functions in nature as a chelation agent produced by several species of fungi, especially Aspergillus oryzae, which has the Japanese common name koji. [ 2 ] [ 3 ] [ 4 ] Kojic acid is a by-product in the fermentation process of malting rice, for use in the manufacturing of sake, the Japanese rice wine. [ 2 ]
Maltol is a white crystalline powder that is soluble in hot water and other polar solvents. Like related 3-hydroxy-4-pyrones such as kojic acid, it binds to hard metal centers such as Fe 3+, Ga 3+, Al 3+, and VO 2+.
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Benzopyran is a polycyclic organic compound that results from the fusion of a benzene ring to a heterocyclic pyran ring.. According to current IUPAC nomenclature, the name chromene used in previous recommendations is retained; however, systematic ‘benzo’ names, for example 2H-1-benzopyran, are preferred IUPAC names for chromene, isochromene, chromane, isochromane, and their chalcogen ...
From January 2008 to December 2012, if you bought shares in companies when Thomas H. Kean joined the board, and sold them when he left, you would have a -67.6 percent return on your investment, compared to a -2.8 percent return from the S&P 500.