503-11-7Relevant academic research and scientific papers
Characterization of the enantioselective properties of the quinohemoprotein alcohol dehydrogenase of Acetobacter pasteurianus LMG 1635. 1. Different enantiomeric ratios of whole cells and purified enzyme in the kinetic resolution of racemic glycidol
Machado, Sonia Salgueiro,Wandel, Ute,Jongejan, Jaap A.,Straathof, Adrie J. J.,Duine, Johannis A.
, p. 10 - 20 (1999)
Resting cells of Acetobacter pasteurianus LMG 1635 (ATCC 12874) show appreciable enantioselectivity (E=16-18) in the oxidative kinetic resolution of racemic 2,3-epoxy-1-propanol, glycidol. Distinctly lower values (E=7-9) are observed for the ferricyanide-coupled oxidation of glycidol by the isolated quinohemoprotein alcohol dehydrogenase, QH-ADH, which is responsible for the enantiospecific oxidation step in whole cells. The accuracy of E-values from conversion experiments could be verified using complementary methods for the measurement of enantiomeric ratios. Effects of pH, detergent, the use of artificial electron acceptors, and the presence of intermediate aldehydes, could be accounted for. Measurements of E-values at successive stages of the purification showed that the drop in enantioselectivity correlates with the separation of QH-ADH from the cytoplasmic membrane. It is argued that the native arrangement of QH-ADH in the membrane-associated complex favors the higher E-values. The consequences of these findings for the use of whole cells versus purified enzymes in biocatalytic kinetic resolutions of chiral alcohols are discussed.
Highly selective and efficient olefin epoxidation with pure inorganic-ligand supported iron catalysts
Zhou, Zhuohong,Dai, Guoyong,Ru, Shi,Yu, Han,Wei, Yongge
supporting information, p. 14201 - 14205 (2019/10/02)
Over the past two decades, there have been major developments in the transition iron-catalyzed selective oxidation of alkenes to epoxides; a common structure found in drug, isolated natural products, and fine chemicals. Many of these approaches have enabled highly efficient and selective epoxidation of alkenes via the design of specialized ligands, which facilitates to control the activity and selectivity of the reactions catalyzed by iron atom. Herein, we report the development of the olefin epoxidation with inorganic-ligand supported iron-catalysts using 30% H2O2 as an oxidant, and the mechanism is similar to iron-porphyrin type. With the catalyst 1, (NH4)3[FeMo6O18(OH)6], various aromatic and aliphatic alkenes were successfully transformed into the corresponding epoxides with excellent yields as well as chemo- and stereo-selectivity. This catalytic system possesses the advantages of being able to avoid the use of expensive, toxic, air/moisture sensitive and commercially unavailable organic ligands. The generality of this methodology is simple to operate and exhibits high catalytic activity as well as excellent stability, which gives it the potential to be used on an industrial scale, and maybe opens a way for the catalytic oxidation reaction via inorganic-ligand coordinated iron catalysis.
Efficient epoxidation of electron-deficient alkenes with hydrogen peroxide catalyzed by [γ-PW10O38V2(μ-OH) 2]3-
Kamata, Keigo,Sugahara, Kosei,Yonehara, Kazuhiro,Ishimoto, Ryo,Mizuno, Noritaka
scheme or table, p. 7549 - 7559 (2011/08/03)
A divanadium-substituted phosphotungstate, [γ-PW10O 38V2(μ-OH)2]3- (I), showed the highest catalytic activity for the H2O2-based epoxidation of allyl acetate among vanadium and tungsten complexes with a turnover number of 210. In the presence of I, various kinds of electron-deficient alkenes with acetate, ether, carbonyl, and chloro groups at the allylic positions could chemoselectively be oxidized to the corresponding epoxides in high yields with only an equimolar amount of H2O2 with respect to the substrates. Even acrylonitrile and methacrylonitrile could be epoxidized without formation of the corresponding amides. In addition, I could rapidly (min) catalyze epoxidation of various kinds of terminal, internal, and cyclic alkenes with H;bsubesubbsubesub& under the stoichiometric conditions. The mechanistic, spectroscopic, and kinetic studies showed that the I-catalyzed epoxidation consists of the following three steps: 1) The reaction of I with H;bsubesubbsubesub& leads to reversible formation of a hydroperoxo species [I;circbsubesubbsubesubbsubesubcirccircbsupesup& (II), 2) the successive dehydration of II forms an active oxygen species with a peroxo group [ 2:2-O2)]3- (III), and 3) III reacts with alkene to form the corresponding epoxide. The kinetic studies showed that the present epoxidation proceeds via III. Catalytic activities of divanadium-substituted polyoxotungstates for epoxidation with H 2O2 were dependent on the different kinds of the heteroatoms (i.e., Si or P) in the catalyst and I was more active than [γ-SiW10O38V2(μ-OH)2] 4-. On the basis of the kinetic, spectroscopic, and computational results, including those of [γ-SiW10O38V 2(μ-OH)2]4-, the acidity of the hydroperoxo species in II would play an important role in the dehydration reactivity (i.e., k3). The largest k3 value of I leads to a significant increase in the catalytic activity of I under the more concentrated conditions. Copyright
Epoxidation of acrylic acid by tetraethylammonium chlorochromate in an aquo-acetic acid-A kinetic study
Awasthi, Anupam,Dipti,Singh
experimental part, p. 410 - 412 (2011/11/07)
Tetraethylammonium chlorochromate oxidised acrylic acid in aqueous acetic acid (50 % v/v) medium in presence of perchloric acid to the epoxide as the oxidation product. The rate of the reaction was dependent on the first power of the concentration of oxidant, substrate and acid. Ionic strength variation has no effect on the reaction rate. The reaction does not induce polymerization. The reaction rate increased with increasing amount of acetic acid in the mixture. Thermodynamic and activation parameters for the reaction have been computed from the data on the temperature dependence. A suitable mechanism consistent with the observed kinetic results has been postulated.
Design, synthesis and biological evaluation of glutathione peptidomimetics as components of anti-Parkinson prodrugs
More, Swati S.,Vince, Robert
supporting information; experimental part, p. 4581 - 4588 (2009/06/06)
Plethoras of CNS-active drugs fail to effect their pharmacologic response due to their in vivo inability to cross the blood-brain barrier (BBB). The classical prodrug approach to overcome this frailty involves lipophilic derivatives of the polar drug, but we herein report a novel approach by which endogenous transporters at BBB are exploited for brain drug delivery. The crucial role played by glutathione in pathogenesis of Parkinson's and the presence of its influx transporters at the basolateral membrane of BBB served as the basis for our anti-Parkinson prodrug design strategy. A metabolically stable analogue of glutathione is used as a carrier for delivery of dopamine and adamantamine. An account of successful syntheses of these prodrugs along with their transport characteristics and stability determination is discussed.
SUBSTITUTED QUINAZOLINE DERIVATIVES AND THEIR USE AS TYROSINE KINASE INHIBITORS
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Page 50, (2010/02/07)
This invention provides compounds of formula (1) wherein X is C3-7 cycloalkyl, pyridinyl, pyrimidinyl or phenyl ring optionally substituted as described in claim 1, R1, R3 and R4 are chosen from the groups listed in claim 1. R2 is chosen from various unsaturated acyl groups listed in claim 1, with certain compounds being disclaimed. Use as tyrosine kinase inhibitors for the treatment of cancer and certain kidney diseases such as polycystic kidney disease.
Mechanistic studies on the oxidation of acrylic acid by quinolinium chlorochromate (QCC)
Mishra, Kanchan,Singh, Jai Veer,Pandey, Archna
, p. 15 - 23 (2007/10/03)
The kinetics of oxidation of acrylic acid with a recently developed new mild Cr(VI) reagent quinolinium chlorochromate (QCC) has been investigated in acetic acid-water mixture (50% v/v). The order in [QCC], [acrylic acid] and [H+] is unity. The increase in the amount of acetic acid in its reaction mixture increases the rate. The effect of ionic strength is negligible. The reaction rates have been determined at different temperatures and the activation parameters have been computed. Stoichiometry indicates that one mole of acrylic acid reacts with one mole of QCC. The mechanisn, consistent with the observed results has been discussed.
Homogeneous Aqueous Oxidation of Organic Molecules by OxoneR and Catalysis by a Water-Soluble Manganese Porphyrin Complex
Zheng, Tu-Cai,Richardson, David E.
, p. 833 - 836 (2007/10/02)
Peroxymonosulfate (KHSO5) oxidizes a wide variety of water-soluble organic molecules in aqueous solutions, and the reactions are generally more rapid in phosphate buffer (pH 6-7) than in pure water.A water-soluble porphyrin complex, meso-tetrakis(4-N-methylpyridyl)porphyrinatomanganese(III) chloride, catalyzes epoxidation and hydroxylation under neutral pH conditions.
Etude par la Modelisation Moleculaire de la Regioselectivite de l'Ouverture des Acides Glycidiques par les Amines Aliphatiques
Grosjean, F.,Huche, M.,Larcheveque, M.,Legendre, J. J.,Petit, Y.
, p. 9325 - 9334 (2007/10/02)
A model for glycidic acids opening reaction by ammonia and amines has been suggested from semi-empiric orbital calculations.It provides a way for evaluating the different interactions between the incoming nucleophile and the oxirane substituents.Steric and coulombic interactions of the carboxylate in staggered conformation (cis substitution) has a major influence to rationalize experimental regioselectivity.
