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Pyranone
Pyrones or pyranones are a class of heterocyclic chemical compounds. They contain an unsaturated six-membered ring, which has one oxygen atom and a carbonyl functional group. There are two isomers, denoted as 2-pyrone and 4-pyrone. The 2-pyrone (or α-pyrone) structure is a lactone and is found in nature as part of the coumarin ring system. The 4-pyrone (or γ-pyrone) structure is an ether–ketone found in some natural chemical compounds such as chromone, maltol and kojic acid. See also * Furanone, which has one fewer carbon atom in the ring. * Pyridone Pyridone may refer to several organic compounds with the formula : *2-Pyridone *3-hydroxypyridine *4-Pyridone These can adopt three tautomers, a oxo form, a zwitterion form, and a enol form. Whereas 2-pyridone (α) and 4-pyridone (γ) predominantl ...s, which contain a nitrogen in place of the oxygen that is part of the ring References {{heterocyclic-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2-Pyranone
2-Pyrone (α-pyrone or pyran-2-one) is an unsaturated cyclic chemical compound with the molecular formula C5H4O2. It is isomeric with 4-pyrone. 2-Pyrone is used in organic synthesis as a building block for more complex chemical structures because it may participate in a variety of cycloaddition reactions to form bicyclic lactones. For example, it readily undergoes Diels-Alder reactions with alkynes producing, upon loss of carbon dioxide, substituted benzenes. The Gogte Synthesis (1938) is a method for the alkylation of certain pyrones with acid chlorides. The parent 2-pyrone can be produced from decarboxylation of coumalic acid. Derivatives The most common natural products containing a 2-pyrone are the bufanolides and kavalactones. Oxovitisin A, a pyranoanthocyanin found in wine, also contains a 2-pyrone element. 6-Amyl-α-pyrone (6PP) is a derivative of 2-pyrone, found in animal foods and heated beef. Due to its good organoleptic properties with coconut aroma, it is used as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coumarin
Coumarin () or 2''H''-chromen-2-one is an aromatic organic chemical compound with formula . Its molecule can be described as a benzene molecule with two adjacent hydrogen atoms replaced by an unsaturated lactone ring , forming a second six-membered heterocycle that shares two carbons with the benzene ring. It belongs to the benzopyrone chemical class and is considered a lactone. Coumarin is a colorless crystalline solid with a sweet odor resembling the scent of vanilla and a bitter taste. It is found in many plants, where it may serve as a chemical defense against predators. While coumarin is not an anticoagulant, its 3-alkyl-4-hydroxy derivatives, such as the fungal metabolite dicoumarol, inhibit synthesis of vitamin K, a key component in blood clotting. A related compound, the prescription drug anticoagulant warfarin, is used to inhibit formation of blood clots, deep vein thrombosis, and pulmonary embolism. Etymology Coumarin is derived from , the French word for the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Furanone
2-Furanone is a heterocyclic organic compound. It is also known as γ-crotonolactone (GCL), as it is formally the lactone derived from γ-hydroxy isocrotonic acid. The chemical is colloquially called "butenolide", and is the parent structure for the butenolide class of compounds. It is a colourless liquid. Synthesis and reactions 2-Furanone is prepared by oxidation of furfural: : It exists in equilibrium with the tautomer 2-hydroxy furan, which serves as an intermediate in the interconversion between the β- and α-furanones. The β form is the more stable. The interconversion is catalyzed by base. 2-Furanones can be converted to furans by a two-step process of reduction followed by dehydration. Furanone is thought to contribute to the unique taste of Maple syrup Maple syrup is a sweet syrup made from the sap of maple trees. In cold climates, these trees store starch in their trunks and roots before winter; the starch is then converted to sugar that rises in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kojic Acid
Kojic acid is an organic compound with the formula . It is a derivative of 4-Pyrone, 4-pyrone that functions in nature as a chelation agent produced by several species of fungus, especially ''Aspergillus oryzae'', which has the Japanese common name ''koji''. Kojic acid is a by-product in the fermentation process of malting rice, for use in the manufacturing of sake, the Japanese rice wine. It is a mild inhibitor of the formation of pigment in plant and animal tissues, and is used in food and cosmetics to preserve or change colors of substances. It forms a bright red complex with ferric ions. Biosynthesis 13C-Labeling studies have revealed at least two pathways to kojic acid. In the usual route, dehydratase enzymes convert glucose to kojic acid. Pentoses are also viable precursors in which case dihydroxyacetone is invoked as an intermediate. Applications Kojic acid may be used on cut fruits to prevent redox, oxidative browning, in seafood to preserve pink and red colors, and in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maltol
Maltol is a naturally occurring organic compound that is used primarily as a flavor enhancer. It is found in nature in the bark of larch trees and in the needles of pine trees, and is produced during the roasting of malt (from which it gets its name) and in the baking of bread. It has the odor of caramel and is used to impart a pleasant aroma to foods and fragrances. It is used as a flavor enhancer, is designated in the U.S. as INS number 636, and is known in the European E number food additive series as E636. Chemistry Maltol is a white crystalline powder that is soluble in hot water and other polar solvents. Like related 3-hydroxy-4-Pyrylium salt, pyrones such as kojic acid, it binds to HSAB theory, hard metal centers such as Fe3+, Ga3+, Al3+, and VO2+. Related to this property, maltol has been reported to greatly increase aluminium uptake in the body and to increase the oral bioavailability of gallium and iron. Maltol's strong metal binding affinity (good iron chelator ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromone
Chromone (or 1,4-benzopyrone) is a derivative of benzopyran with a substituted keto group on the pyran ring. It is an isomer of coumarin. Derivatives of chromone are collectively known as ''chromones''. Most, though not all, chromones are also phenylpropanoids. Examples * 6,7-dimethoxy-2,3-dihydrochromone has been isolated from '' Sarcolobus globosus''. * Eucryphin, a chromone rhamnoside, can be isolated from the bark of ''Eucryphia cordifolia''. * Cromolyn (disodium cromoglicate) was found to inhibit antigen challenge as well as stress induced symptoms.HOWELL, J.B. & ALTOUNYAN, R.E. (1967). A double-blind trial of disodium cromoglycate in the treatment of allergic bronchial asthma. Lancet, 2, 539–542Abstract/ref> Cromoglicate is used as a mast cell stabilizer in allergic rhinitis, asthma and allergic conjunctivitis. * Nedocromil sodium was found to have a somewhat longer half-life than cromolyn; however, production was discontinued in the US in 2008. * Xanthone with a se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ketone
In organic chemistry, a ketone is an organic compound with the structure , where R and R' can be a variety of carbon-containing substituents. Ketones contain a carbonyl group (a carbon-oxygen double bond C=O). The simplest ketone is acetone (where R and R' are methyl), with the formula . Many ketones are of great importance in biology and industry. Examples include many sugars (ketoses), many steroids, ''e.g.'', testosterone, and the solvent acetone. Nomenclature and etymology The word ''ketone'' is derived from ''Aketon'', an old German word for ''acetone''. According to the rules of IUPAC nomenclature, ketone names are derived by changing the suffix ''-ane'' of the parent alkane to ''-anone''. Typically, the position of the carbonyl group is denoted by a number, but traditional nonsystematic names are still generally used for the most important ketones, for example acetone and benzophenone. These nonsystematic names are considered retained IUPAC names, although some introdu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ether
In organic chemistry, ethers are a class of compounds that contain an ether group, a single oxygen atom bonded to two separate carbon atoms, each part of an organyl group (e.g., alkyl or aryl). They have the general formula , where R and R′ represent the organyl groups. Ethers can again be classified into two varieties: if the organyl groups are the same on both sides of the oxygen atom, then it is a simple or symmetrical ether, whereas if they are different, the ethers are called mixed or unsymmetrical ethers. A typical example of the first group is the solvent and anaesthetic diethyl ether, commonly referred to simply as "ether" (). Ethers are common in organic chemistry and even more prevalent in biochemistry, as they are common linkages in carbohydrates and lignin. Structure and bonding Ethers feature bent linkages. In dimethyl ether, the bond angle is 111° and C–O distances are 141 pm. The barrier to rotation about the C–O bonds is low. The bonding of ox ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lactone
Lactones are cyclic carboxylic esters. They are derived from the corresponding hydroxycarboxylic acids by esterification. They can be saturated or unsaturated. Lactones are formed by lactonization, the intramolecular esterification of the corresponding hydroxycarboxylic acids. Nomenclature Greek alphabet#Letters, Greek prefixes in alphabetical order indicate ring size. Lactones are usually named according to the precursor acid molecule (''aceto'' = 2 carbon atoms, ''propio'' = 3, ''butyro'' = 4, ''valero'' = 5, ''capro'' = 6, etc.), with a ''-lactone'' suffix and a Greek letter prefix that specifies the number of carbon atoms in the heterocycle — that is, the distance between the relevant -OH and the -COOH groups along said backbone. The first carbon atom after the carbon in the -COOH group on the parent compound is labelled α, the second will be labeled β, and so forth. Therefore, the prefixes also indicate the size of the lactone ring: α-lactone = 3-membered ring, β-lac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
4-Pyranone
4-Pyrone (γ-pyrone or pyran-4-one) is an unsaturated cyclic chemical compound with the molecular formula C5H4O2.It is isomeric with 2-pyrone. Preparation 4-Pyrone is prepared via the thermal decarboxylation of chelidonic acid. Reactions 4-Pyrone and its derivatives react with amines in protic solvents to form 4-Pyridones. Derivatives 4-Pyrone forms the central core of several natural chemical compounds, including maltol, meconic acid, kojic acid, and of the important class of the Flavones. : See also * Pyrone * 4-Pyridone * Dehydroacetic acid Dehydroacetic acid is an organic compound which has several industrial applications. The compound is classified as a pyrone derivative. It presents as an odorless, colorless to white crystalline powder, almost insoluble in water and moderately so ... References {{DEFAULTSORT:Pyrone, 4- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2-pyrone
2-Pyrone (α-pyrone or pyran-2-one) is an Saturated and unsaturated compounds, unsaturated cyclic chemical compound with the molecule, molecular formula C5H4O2. It is isomeric with 4-pyrone. 2-Pyrone is used in organic synthesis as a building block for more complex chemical structures because it may participate in a variety of cycloaddition reactions to form bicyclic lactones. For example, it readily undergoes Diels-Alder reactions with alkynes producing, upon loss of carbon dioxide, substituted benzenes. The Gogte Synthesis (1938) is a method for the alkylation of certain pyrones with acid chlorides. The parent 2-pyrone can be produced from decarboxylation of coumalic acid. Derivatives The most common natural products containing a 2-pyrone are the bufanolides and kavalactones. Oxovitisin A, a pyranoanthocyanin found in wine, also contains a 2-pyrone element. 6-Amyl-α-pyrone (6PP) is a derivative of 2-pyrone, found in animal foods and heated beef. Due to its good organoleptic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
