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Naphthoquinone
Naphthoquinones constitute a class of organic compounds structurally related to naphthalene. Two isomers are common for the parent naphthoquinones: * 1,2-Naphthoquinone * 1,4-Naphthoquinone Natural products * Alkannin * Hexahydroxy-1,4-naphthalenedione * Juglone * Lapachol * Lawsone * Menatetrenone * 2-Methoxy-1,4-naphthoquinone, a compound found in '' Impatiens'' species * Nigrosporin B * Phylloquinone * Plumbagin * Spinochrome B * Spinochrome D * Vitamin K and related compounds ** Phylloquinone ** Vitamin K2 ** Menadione Menadione is a natural organic compound with the formula C6H4(CO)2C2H(CH3). It is an analog of 1,4-naphthoquinone with a methyl group in the 2-position. It is sometimes called vitamin K3. Use is allowed as a nutritional supplement in animal ... (2-Methyl-1,4-naphthoquinone) Synthetic naphthoquinones * 5,8-Dihydroxy-1,4-naphthoquinone and dihydroxynaphthoquinones * Atovaquone * Buparvaquone, an antiprotozoal drug used in veterinary ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1,4-Naphthoquinone
1,4-Naphthoquinone or para-naphthoquinone is a quinone derived from naphthalene. It forms volatile yellow triclinic crystals and has a sharp odor similar to benzoquinone. It is almost insoluble in cold water, slightly soluble in petroleum ether, and more soluble in polar organic solvents. In alkaline solutions it produces a reddish-brown color. Vitamin K is a derivative of 1,4-naphthoquinone. It is a planar molecule with one aromatic ring fused to a quinone subunit. It is an isomer of 1,2-naphthoquinone. Preparation The industrial synthesis involves aerobic oxidation of naphthalene over a vanadium oxide catalyst: :CH + 3/2 O → CHO + HO In the laboratory, naphthoquinone can be produced by the oxidation of a variety of naphthalene compounds. An inexpensive route involves oxidation of naphthalene with chromium trioxide. Reactions 1,4-Naphthoquinone acts as strong dienophile in Diels-Alder reaction. Its adduct with 1,3-butadiene can be prepared by two methods: 1) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1,2-Naphthoquinone
1,2-Naphthoquinone or ''ortho''-naphthoquinone is a polycyclic aromatic organic compound with formula . This yellow solid is prepared by oxidation of 1-amino-2-hydroxynaphthalene with ferric chloride. Occurrence This diketone (an ortho-quinone) is a metabolite of naphthalene. It arises from the naphthalene-1,2-oxide. It is also found in diesel exhaust particles. The accumulation of this toxic metabolite in rats from doses of naphthalene has been shown to cause eye damage, including the formation of cataracts. See also * 1,4-Naphthoquinone, an isomer In chemistry, isomers are molecules or polyatomic ions with identical molecular formula – that is, the same number of atoms of each element (chemistry), element – but distinct arrangements of atoms in space. ''Isomerism'' refers to the exi ... of 1,2-naphthoquinone References External links * * {{DEFAULTSORT:Naphthoquinone, 1, 2- 1,2-Naphthoquinones ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Naphthoquinones
Naphthoquinones constitute a class of organic compounds structurally related to naphthalene. Two isomers are common for the parent naphthoquinones: * 1,2-Naphthoquinone * 1,4-Naphthoquinone Natural products * Alkannin * Hexahydroxy-1,4-naphthalenedione * Juglone * Lapachol * Lawsone * Menatetrenone * 2-Methoxy-1,4-naphthoquinone, a compound found in ''Impatiens'' species * Nigrosporin B * Phylloquinone * Plumbagin * Spinochrome B * Spinochrome D * Vitamin K and related compounds ** Phylloquinone ** Vitamin K2 ** Menadione (2-Methyl-1,4-naphthoquinone) Synthetic naphthoquinones * 5,8-Dihydroxy-1,4-naphthoquinone and dihydroxynaphthoquinones * Atovaquone * Buparvaquone, an antiprotozoal drug used in veterinary medicine * Diazonaphthoquinone, a diazo derivative of naphthoquinone * 1,2-Naphthoquinone, from the biodegradation of naphthalene. See also * Hydroxynaphthoquinones References {{Naphthoquinone Naphthoquinones, pt:Naftoquinona ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spinochrome B
Spinochrome B (2,3,5,7-tetrahydroxynaphthoquinone) is an organic compound with formula , formally derived from 1,4-naphthoquinone through the replacement of four hydrogen atoms by hydroxyl (OH) groups. Spinochrome B occurs naturally as pigment in the shell and spines of sea urchins such as the Japanese dull red species ''aka-uni'' ('' Pseudocentrotus depressus''), the greenish-black ''murasaki-uni'' ('' Heliocidaris crassispina''), and the brown ''bafun-uni'' ('' Strongylocentrotus pulcherrimus'').Chika KURODA and Masae OKAJIMA (1958), ''Studies on the Derivatives of Naphthoquinones, XIV. The pigments of sea urchins, IX''. Proc. Japan Acad., volume 34, pages 616--618Online versionaccessed on 2010-02-01. Pigment M2 is drawn as 2,3,6,8-thNQ but that is the same as 2,3,5,7-thNQ. The genus ''Heliocedaris'' should be ''Heliocidaris'' and the species ''purcherrmus'' should be ''pulcherrimus''.Chika KURODA and Masae OKAJIMA (1967), ''Studies on the Derivatives of Naphthoquinones, XVIII. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexahydroxy-1,4-naphthalenedione
Spinochrome E (also called 2,3,5,6,7,8-hexahydroxy-1,4-naphthalenedione or hexahydroxynaphthoquinone) is a polyhydroxylated 1,4-naphthoquinone pigment found in sea urchin shell ("test"), spine, gonads, coelomic fluid, and eggs, of sea urchin commonly known as spinochromes. These natural phenolic compounds are quinones with potential pharmacological properties. The several hydroxyl groups are appropriate for free-radical scavenging, which diminishes ROS and prevents redox imbalance. Mechanisms are described such as scavenging of reactive oxygen species (ROS), interaction with lipid peroxide radicals, chelation of metal ions, inhibition of lipid peroxidation and regulation of the cell redox potential. The chemical formula of spinochrome E, , indicates that it has one extra hydroxyl group relative to echinochrome A and it is formally derived from naphthoquinone (1,4-naphtalenedione) through replacement of all six hydrogen atoms by hydroxyl (OH) groups. The numerical prefixes "2, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Juglone
Juglone, also called 5-hydroxy-1,4-naphthalenedione (IUPAC) is a phenolic organic compound with the molecular formula C10H6O3. In the food industry, juglone is also known as C.I. Natural Brown 7 and C.I. 75500. It is insoluble in benzene but soluble in dioxane, from which it crystallizes as yellow needles. It is an isomer of lawsone, which is the active dye compound in the henna leaf. Juglone occurs naturally in the leaves, roots, husks, fruit ( the epicarp), and bark of plants in the Juglandaceae family, particularly the black walnut ('' Juglans nigra''), and is toxic or growth-stunting to many types of plants. It is sometimes used as an herbicide, as a dye for cloth and inks, and as a coloring agent for foods and cosmetics. History The allelopathic effects of walnut trees on other plants were observed as far back as the 1st century CE. Juglone itself was first isolated from black walnut in 1856, and was identified as the compound responsible for its allelopathic effect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydroxynaphthoquinone
A hydroxynaphthoquinone (formula: ) is any of several organic compounds that can be viewed as derivatives of a naphthoquinone through replacement of one hydrogen atom (H) by a hydroxyl group (-OH). In general, the term may mean any naphthoquinone derivative where any number ''n'' of hydrogens have been replaced by ''n'' hydroxyls, so that the formula is . In this case the number ''n'' (which is between 1 and 6) is indicated by a multiplier prefix (mono-, di-, tri-, tetra-, penta-, or hexa-). The unqualified term "hydroxynaphthoquinone" usually means a derivative of 1,4-naphthoquinone. Other hydroxy- compounds can be derived from other isomers of the latter, such as 1,2-naphthoquinone and 2,6-naphthoquinone. The IUPAC nomenclature uses dihydronaphthalenedione instead of "naphthoquinone", with the necessary prefixes to indicate the positions of the carbonyl oxygens (=O) — as in 5,8-dihydroxy-1a,8a-dihydronaphthalene-1,4-dione (= 5,8-dihydroxy-1,4-naphthoquinone). The hydroxyna ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Menadione
Menadione is a natural organic compound with the formula C6H4(CO)2C2H(CH3). It is an analog of 1,4-naphthoquinone with a methyl group in the 2-position. It is sometimes called vitamin K3. Use is allowed as a nutritional supplement in animal feed because of its vitamin K activity. Biochemistry Menadione is converted to vitamin K2 (specifically, MK-4) by the prenyltransferase action of vertebrate UBIAD1. This reaction requires the hydroquinone (reduced) form of K3, menadiol, produced by NQO1. Menadione is also a circulating form of vitamin K, produced in small amounts (1–5%) after intestinal absorption of K1 and K2. This circulation explains the uneven tissue distribution of MK-4, especially since menadione can penetrate the blood–brain barrier. The cleavage enzyme is yet to be identified. As K3 is known to be toxic in large amounts, researchers speculate that the cleavage process is closely regulated. Terminology The compound is variously known as vitamin K3 an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vitamin K2
Vitamin K2 or menaquinone (MK) () is one of three types of vitamin K, the other two being vitamin K1 ( phylloquinone) and K3 (menadione). K2 is both a tissue and bacterial product (derived from vitamin K1 in both cases) and is usually found in animal products or fermented foods. The number ''n'' of isoprenyl units in their side chain differs and ranges from 4 to 13, hence vitamin K2 consists of various forms. It is indicated as a suffix (-n), e. g. MK-7 or MK-9. * The most common in the human diet is the short-chain, water-soluble menatetrenone (MK-4), which is commonly found in animal products. However, at least one published study concluded that "MK-4 present in food does not contribute to the vitamin K status as measured by serum vitamin K levels." The MK-4 in animal (including human) tissue is made from dietary plant vitamin K1. This process can be accomplished by animal tissues alone, as it proceeds in germ-free rodents. * Long-chain menaquinones (longer than MK-4) include ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vitamin K
Vitamin K is a family of structurally similar, fat-soluble vitamers found in foods and marketed as dietary supplements. The human body requires vitamin K for post-translational modification, post-synthesis modification of certain proteins that are required for blood coagulation ("K" from Danish ''koagulation'', for "coagulation") and for controlling molecular binding, binding of calcium in bones and other tissue (biology), tissues. The complete synthesis involves final modification of these "Gla proteins" by the enzyme gamma-glutamyl carboxylase that uses vitamin K as a cofactor (biochemistry), cofactor. Vitamin K is used in the liver as the intermediate VKH2 to deprotonate a glutamate residue and then is reprocessed into vitamin K through a vitamin K oxide intermediate. The presence of uncarboxylated proteins indicates a vitamin K deficiency. Carboxylation allows them to bind (chelate) calcium ions, which they cannot do otherwise. Without vitamin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spinochrome D
Spinochrome D (2,3,5,6,8-pentahydroxy-1,4-naphthoquinone) is an organic compound with formula , formally derived from 1,4-naphthoquinone through the replacement of five hydrogen atoms by hydroxyl (OH) groups. Spinochrome D occurs naturally as a brownish red pigment in the shell and spines of sea urchins such as the Japanese ''aka-uni'' ('' Pseudocentrotus depressus'').Chika KURODA and Masae OKAJIMA (1967), ''Studies on the Derivatives of Naphthoquinones, XVIII. The pigments of sea urchins, XIII''. Proc. Japan Acad., volume 43, pages 41--44Online versionaccessed on 2010-02-01. It is soluble in diethyl ether and crystallizes as brownish red needles that sublime at 285−295 °C. The compound gives a yellowish brown solution when treated with sodium hydroxide, a bluish green solution with ferric chloride, and a violet precipitate with lead acetate. It forms a five-fold acetate ester, ()5, that crystallizes from methanol as yellow needles that melt at 185−186 °C. See ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phylloquinone
Phytomenadione, also known as vitamin K1, phylloquinone, or phytonadione, is a vitamin found in food and used as a dietary supplement. It is on the World Health Organization's List of Essential Medicines. It is used to treat certain bleeding disorders, including warfarin overdose, vitamin K deficiency, and obstructive jaundice. Use is typically recommended by mouth, intramuscular injection or injection under the skin. When given by injection benefits are seen within two hours. It is also recommended for preventing and treating vitamin K deficiency bleeding in infants. Many countries in the world choose intramuscular injections in newborn to keep them safe from vitamin K deficiency bleeding. It is considered a safe treatment and saves many children from death and severe neurologic deficit every year. Side effects when given by injection may include pain at the site of injection. Severe allergic reactions may occur when it is injected into a vein or muscle, but this has m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
