81818-54-4Relevant articles and documents
Indirect inhibition of vitamin K epoxide reduction by salicylate
Hildebrandt,Suttie
, p. 586 - 591 (1984)
Salicylate antagonizes the vitamin K-dependent biosynthesis of clotting factors in the rat and produces an elevation of the ratio of vitamin K epoxide to vitamin K in the liver. Vitamin K epoxide is reduced to vitamin K by a vitamin K epoxide reductase, and 1 mM salicylate was required to cause a 50% inhibition of the dithiothreitol-dependent in-vitro reduction of vitamin K epoxide by this enzyme. This enzyme was, however, inhibited 50% by as little as 70-80 μM salicylate when reducing equivalents for the reaction were furnished by endogenous cytosolic reductants. This effect on the cytosolic reductant supply was shown to be unrelated to a previously demonstrated inhibition of DT-diaphorase by salicylate. The concentrations of salicylate at which significant inhibitory effects are exerted in-vitro (50-100 μM) are below the 200 μM levels observed in the liver of rats given an anticoagulating dose of salicylate.
Full racemic phytol composition, and preparation method and application thereof
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Paragraph 0135; 0142-0146, (2020/12/10)
The present invention provides a full racemic phytol composition with high E-configuration content, a preparation method of the full racemic phytol composition and applications of the full racemic phytol composition in preparation of vitamin K1. The full racemic phytol composition comprises Z-configuration full racemic phytol and E-configuration full racemic phytol, wherein a ratio of Z/(Z+E) is less than or equal to 15%. The preparation method comprises the following steps: with isophytol as a raw material, performing halogenation, esterification, ester group removal reaction and the like toobtain the full racemic phytol composition with high E-configuration content.
Improved synthesis of vitamin K1
Ji, Ya-Fei,Zong, Zhi-Min,Wei, Xian-Yong,Tu, Guang-Zhong,Xu, Li,He, Lin-Tao
, p. 763 - 772 (2007/10/03)
With (E/Z)-isomeric phytyl halides as side-chain materials, vitamin K1 is synthesized via a Diels-Alder reaction to activate the free bridgehead hydrogen of 3 for the alkylation and a retro-Diels-Alder reaction to eliminate cyclopentadiene from 2 in a high yield, in which the configuration of the double bond in the phytyl side-chain is retained.
An expeditious route to CoQ(n), Vitamins K1 and K2, and related allylated para-quinones utilizing Ni(0) catalysis
Lipshutz, Bruce H.,Kim, Sung-Kyu,Mollard, Paul,Stevens, Kirk L.
, p. 1241 - 1253 (2007/10/03)
Coupling reactions between vynylalanes and chloromethylated para-quinones, mediated by catalytic amounts of Ni(0), lead directly to allylated products, including coenzyme Q, and vitamins K1 and K2.
A Convenient One-flask Synthesis of Vitamin K
Tso, Hsi-Hwa,Chen, Yu-Jiun
, p. 104 - 105 (2007/10/03)
A facile synthesis of highly pure (E)-form vitamins K1 and K2 by the reaction of 3-substituted isobenzofuranones 2 with vinylic sulfones 1 in one flask is described.
The active site of vitamin K and the role of the vitamin K-dependent carboxylase
Naganathan, Sriram,Hershline, Roger,Ham, Seung Wook,Dowd, Paul
, p. 9831 - 9839 (2007/10/02)
Vitamin K is the blood-clotting vitamin. It participates in the blood coagulation cascade as a carboxylase cofactor. Enzymic oxygenation of vitamin K hydroquinone provides the driving force for the carboxylation of selected glutamates in the proteins of the blood-clotting cascade. The active site of vitamin K has now been defined by 18O-labeling experiments. The oxygenation is completely specific for the carbonyl group adjacent to the quinone methyl group of vitamin K. The experiment makes use of the 18O-labeled vitamin K isotopomers 9 and 10. Thus, oxygenation of 9 with 16O2 occurs at the carbonyl group next to methyl, as shown by exchange of the 18O label at that position. Synthesis of the two 18O-labeled vitamin K isotopomers 9 and 10 was accomplished by cerium(IV)-mediated oxidation in the presence of H218O of the corresponding methyl half-ethers 4 and 8. The position of the label was ascertained by 13C and heteronuclear NOE NMR spectroscopies. A role for the active site thiols on the vitamin K-dependent carboxylase is also suggested. The thiolate anion is an excellent candidate for the weak base that initiates the base strength amplification sequence leading to carboxylation and vitamin K oxide formation.
Catalytic Oxidation of Hydroquinones and Naphthalenediols to 1,4-Quinones with H2O2 in the Presence of Chromium (VI) Oxide-Bistributyltin Oxide and an Application to Vitamin K1 Synthesis
Inoue, Masami,Uragaki, Toshitaka,Enomoto, Saburo
, p. 2075 - 2078 (2007/10/02)
The oxidation of hydroquinones and naphthalenediols to 1,4-quinones was carried out in the presence of a chromium (VI) compound formed from chromium (VI) oxide and bistributyltin oxide with 30percent aqueous H2O2 in benzene-isopropyl ether at 50 deg C.The catalyst was fixed on charcoal and used for the oxidation of dihydrovitamin K1 in ethyl alcohol.
A Chemical Model for the Mechanism of Vitamin K Epoxide Reductase
Preusch, Peter C.,Suttie, J. W.
, p. 3301 - 3305 (2007/10/02)
The reactions of Vitamin K1 epoxide and 2,3-dimethylnaphthoquinone epoxide with dithiothreitol and mercaptoethanol have been studied as a potential model for the mechanism of the enzyme vitamin K epoxide reductase.The reaction proceeds with thiol addition to open the oxirane ring, yielding preferentially the 2-thio-3-hydroxy adduct in the case of vitamin K1 epoxide.Reaction with a second thiol group results in reductive cleavage of this adduct and elimination of water to yield the quinones.All steps are catalyzed by triethylamine.Evidence for a hydroxy-substituted 2,3-dihydronaphthoquinone enolate intermediate in the second step is found in the observation of the corresponding keto compounds as equilibrated side products in the reaction with dithiothreitol.With this reagent, intramolecular reaction to form the cyclic disulfide permits cleavage of the thiol adduct under mild conditions where protonation of the enolate is rapid relative to elimination of the hydroxyl.Isolation and characterization of the intermediates and their conversion to the quinones are described.
CROSS-COUPLING REACTION OF ALLYL BROMIDES WITH ORGANOTIN REAGENTS CATALYZED BY ZINC CHLORIDE
Godschalx, J. P.,Stille, J. K.
, p. 1905 - 1908 (2007/10/02)
Myrcene and β-farnesene have been synthesized by the zinc chloride catalyzed coupling reaction of (2-methylene-3-butenyl)trimethyltin with prenyl bromide and geranyl bromide, respectively; vitamin K1 was synthesized by a similar coupling reaction.
REAKTIONEN VON KOMPLEXLIGANDEN. XXIV. SYNTHESE VON NAPHTHOL-DERIVATEN AUS CARBONYL-CARBEN-KOMPLEXEN UND ALKINEN: REGIOSELEKTIVER EINBAU DES ALKINS IN DAS NAPHTHALIN-GERUEST
Doetz, Karl Heinz,Muehlemeier, Jochen,Schubert, Ulrich,Orama, Olli
, p. 187 - 202 (2007/10/02)
Pentacarbonyl(methoxyphenylcarbene)chromium reacts with various alkynes to give tricarbonyl(4-methoxy-1-naphthol)chromium complexes.Aliphatic n-1-alkynes yield regiospecifically 2-alkylnaphthol compounds; 2-alkynes, however, lead to mixtures of 2,3-dialky
