- Novel hypervalent iodine catalyzed synthesis of α-sulfonoxy ketones: Biological activity and molecular docking studies
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The novel di((camphorsulfonyl)oxy)iodo]benzene (DCIB) was synthesized from [Bis(trifluoroacetoxy)iodo]benzene in the mild conditions. The α-sulfonoxylation of various ketones with novel hypervalent iodine was reported in excellent yield. α-Hydroxyketones
- Atmaca, Ufuk,Alp, Cemalettin,Akincioglu, Hulya,Karaman, Halide Sedef,Gül?in, ?lhami,?elik, Murat
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- Enantioselective Cascade Biocatalysis for Deracemization of Racemic β-Amino Alcohols to Enantiopure (S)-β-Amino Alcohols by Employing Cyclohexylamine Oxidase and ω-Transaminase
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Optically active β-amino alcohols are very useful chiral intermediates frequently used in the preparation of pharmaceutically active substances. Here, a novel cyclohexylamine oxidase (ArCHAO) was identified from the genome sequence of Arthrobacter sp. TYUT010-15 with the R-stereoselective deamination activity of β-amino alcohol. ArCHAO was cloned and successfully expressed in E. coli BL21, purified and characterized. Substrate-specific analysis revealed that ArCHAO has high activity (4.15 to 6.34 U mg?1 protein) and excellent enantioselectivity toward the tested β-amino alcohols. By using purified ArCHAO, a wide range of racemic β-amino alcohols were resolved, (S)-β-amino alcohols were obtained in >99 % ee. Deracemization of racemic β-amino alcohols was conducted by ArCHAO-catalyzed enantioselective deamination and transaminase-catalyzed enantioselective amination to afford (S)-β-amino alcohols in excellent conversion (78–94 %) and enantiomeric excess (>99 %). Preparative-scale deracemization was carried out with 50 mM (6.859 g L?1) racemic 2-amino-2-phenylethanol, (S)-2-amino-2-phenylethanol was obtained in 75 % isolated yield and >99 % ee.
- Zhang, Jian-Dong,Chang, Ya-Wen,Dong, Rui,Yang, Xiao-Xiao,Gao, Li-Li,Li, Jing,Huang, Shuang-Ping,Guo, Xing-Mei,Zhang, Chao-Feng,Chang, Hong-Hong
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p. 124 - 128
(2020/09/21)
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- Ligustrazine-fused cyclic compound and medicine composition thereof, as well as application in medicine thereof
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The invention discloses a ligustrazine-fused cyclic compound and a medicine composition thereof and application in a medicine. The ligustrazine-fused cyclic compound has the following structural general formula I: as shown in the specification. The medicine composition is a medicinal active component for the ligustrazine-fused cyclic compound and a pharmaceutically acceptable carrier, an excipient, a diluent, an adjuvant, a medium or a combination thereof; the ligustrazine-fused cyclic compound and the medicine composition can be used for preventing or treating cardiovascular and cerebrovascular diseases, digestive system diseases, respiratory diseases, the alzheimer's disease, kidney diseases and complications of the above-mentioned diseases due to thrombus and excessive free radicals. The ligustrazine-fused cyclic compound disclosed by the invention has an extremely good inhibition effect on in vitro ADP (adenosine diphosphate)-induced platelet aggregation; meanwhile, compared with the pharmacokinetic property of ligustrazine serving as a female parent, the pharmacokinetic property of the ligustrazine-fused cyclic compound in the body of a rat is obviously improved.
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- An efficient method for selective oxidation of 1,2-diols in water catalyzed by Me2SnCl2
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Dimethyltin(iv)dichloride-catalyzed selective oxidation of 1,2-diols in water was achieved using dibromoisocyanuric acid (DBI) or Br2 as oxidants. The catalyst activates the 1,2-diol moiety through the formation of stannylene acetal in addition to enhancing selectivity. Various cyclic and acyclic 1,2-diol substrates have been selectively oxidized affording α-hydroxyketones in good to excellent yields. This method is safe and simple in operation.
- William, Julius M.,Kuriyama, Masami,Onomura, Osamu
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p. 19247 - 19250
(2013/10/22)
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- Reactions of hydrogen peroxide with acetylacetone and 2- acetylcyclopentanone
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A reaction of acetylacetone with equimolar amount of concentrated aqueous H2O2 in both organic solvents (ButOH, AcOH) and water at various temperatures gave the corresponding 3,5-dihydroxy-1,2- dioxolanes with different configuration of stereogenic centers. In the pres-ence of an excess of H2O2, 3,5-dihydroxy-1,2-dioxolanes were converted to a mixture of 5-hydroperoxy-3-hydroxy-1,2-dioxolanes and further to a mixture of dimeric 1,2-dioxolan-3-ylperoxides. All the peroxides formed exist in solutions as equilibrium mixtures with the starting reagents. A prolonged reflux of solutions of 3,5-dihydroxy-1,2-dioxolanes in ButOH in the presence of a large excess of H2O2 led to the skeletal rearrangements of the substrates to a mixture of propionic acid and hydroxyacetone, which underwent further oxidative transfor-mations. Unlike acetylacetone, 2-acetylcyclopentanone reacted with H2O2 in aqueous phase or in solutions in ButOH under thermodynamic or kinetic control with the formation of the corresponding 5-hydroperoxy-3-hydroxy- 1,2-dioxolanes, rather than 3,5-dihydroxy-1,2-di-oxolanes. Thermodynamically controlled process in solution in AcOH gave a mixture of all four possible hydroperoxyhydroxy-1,2-dioxolanes. These cyclic peroxides in solutions in ButOH or AcOH readily converted to a mixture of AcOH, glutaric, α-methyladipic, and α-hydroxy-α-methyladipic acids. An active α-hydroxylation of the substrate was observed upon reflux of a solution of 2-acetylcyclopentanone and H2O2 in AcOH.
- Novikov,Shestak
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p. 2171 - 2190
(2014/11/07)
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- Preparation of α-oxygenated ketones by the dioxygenation of alkenyl boronic acids
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Two in two: Dioxygenation of alkenyl boronic acids has been achieved with N-hydroxyphthalimide. The two-step process involves etherification of an alkenyl boronic acid with N-hydroxyphthalimide followed by a [3,3] rearrangement. The dioxygenated product can then be hydrolyzed to form either the corresponding α-hydroxy ketone or the α-benzoyloxy ketone. Copyright
- Patil, Aditi S.,Mo, Dong-Liang,Wang, Heng-Yen,Mueller, Daniel S.,Anderson, Laura L.
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supporting information; experimental part
p. 7799 - 7803
(2012/09/08)
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- Cu(II)-catalyzed acylation by thiol esters under neutral conditions: Tandem acylation-wittig reaction leading to a one-pot synthesis of butenolides
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The first catalytic acylation of alcohols with a thiol ester present in Wittig reagents under neutral conditions catalyzed by the Cu(II) salt through a push-pull mechanism is reported. Furthermore, a new methodology for the one-pot lactonization of acyloins by a copper catalyst is developed. The synthetic utility of this method for the synthesis of natural products is shown.
- Matsuo, Kazumasa,Shindo, Mitsuru
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supporting information; experimental part
p. 5346 - 5349
(2011/01/05)
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- Efficient oxidation of 1,2-diols into a-hydroxyketones catalyzed by organotin compounds
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Electrochemical oxidation of 1,2-diols with a catalytic amount of an organotin compound and a bromide ion as mediators has been developed. Various cyclic and acyclic 1,2-diols were oxidized into the corresponding α-hydroxyketones in good to excellent yields without C-C bond cleavage. Also, oxidation with the use of chemical oxidants was accomplished in the presence of a catalytic amount of an organotin compound. These reactions could discriminate 1,2-diols from isolated hydoxyl groups or 1,3-diols. In the case of a conformationally restricted cyclic 1,2-diol, the axial hydroxyl group was oxidized exclusively. Mono-, di-, and trialkylated tin compounds were examined as mediators and dialkylated tin compounds showed higher catalytic activity than mono- and trisubstituted ones. Me2SnCl2 was found to be the most suitable mediator for the selective oxidation..
- Maki, Toshihide,Iikawa, Shinya,Mogami, Gen,Harasawa, Hitomi,Matsumura, Yoshihiro,Onomura, Osamu
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experimental part
p. 5364 - 5370
(2009/12/22)
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- METHOD AND COMPOSITIONS FOR TREATING HIV INFECTIONS
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Described herein are compounds and compositions that are useful in the treatment of HIV, AIDS, and AIDS-related diseases. In addition, compounds are described herein that are capable of inhibiting the dimerization of HIV proteases.
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Page/Page column 35
(2008/12/08)
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- Microwave-assisted synthesis of α-hydroxy ketone and α-diketone and pyrazine derivatives from α-halo and α,α′-dibromo ketone
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A novel reaction of α-halo ketone (α-bromo and α-chloro ketone) with irradiation under microwave gave the corresponding α-hydroxyketone and pyrazine derivative in good yields. In the case of α,α′-dibromo ketone, α-diketone was obtained. This reaction affords a new, clean and convenient synthetic method for α-hydroxyketone, α-diketone, α-chloro ketone and pyrazine derivative.
- Utsukihara, Takamitsu,Nakamura, Hiroaki,Watanabe, Masashige,Akira Horiuchi
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p. 9359 - 9364
(2008/01/27)
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- Diastereoselective [4 + 4]-photocycloaddition reactions of pyran-2-ones: Rapid access to functionalized 5-8-5 skeletons
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Fused bicyclic pyran-2-ones with pendant furan side chains and an oxygenated stereogenic center adjacent to the pyranone ring oxygen were prepared via FeCl3-catalyzed Michael addition. Irradiation furnished the corresponding lactone-bridged tri
- Song, Dong,McDonald, Robert,West
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p. 4075 - 4078
(2007/10/03)
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- Investigations into the selective oxidation of vicinal diols to α-hydroxy ketones with the NaBrO3/NaHSO3 reagent: PH dependence, stoichiometry, substrates and origin of selectivity
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The NaBrO3/NaHSO3 reagent is one of the few oxidizing agents that chemoselectively oxidizes vicinal diols to α-hydroxy ketones with little overoxidation to the corresponding vicinal-dione or dicarboxylic acid. Oxidation reactions performed with this reagent showed strong pH dependence. cis-Vicinal diols reacted faster than trans-vicinal diols to the α-hydroxy ketone product. Hydroxy functional groups at axial ring positions were more readily oxidized than equatorial hydroxy groups. The application of the NaBrO3/NaHSO3 reagent for the chemoselective oxidation of vicinal diols was limited to simple systems and failed with more complex monosaccharide compounds probably due to acid catalyzed dehydrogenation reactions. Despite the simple reaction set-up and good selectivity towards the α-hydroxy ketone product, the actual oxidation reaction mechanism is highly complex and postulated to involve at least six different equilibria with a plethora of bromine containing species. A possible oxidation reaction mechanism is discussed.
- Bierenstiel, Matthias,D'Hondt, Paul J.,Schlaf, Marcel
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p. 4911 - 4917
(2007/10/03)
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- Product selectivity in the electroreduction of thioesters
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The electroreduction of differently substituted aromatic and aliphatic thioesters (RCOSR′) led to regioselective reactions depending on the nature of the substituents. Thus, the cleavage between the carbonyl group and the SR′ group afforded α-diketones an
- We?wer,Olivero,Du?ach
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p. 1709 - 1714
(2007/10/03)
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- Studies on the stability of the cyclobutane β-aminoacid skeleton: A cautionary tale
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The 2-amino-1-cyclobutanecarboxylic acid skeleton undergoes facile retro-Mannich type ring opening in solution, which may lead to unexpected by-products during its synthesis or manipulation.
- Aitken, David J.,Gauzy, Christine,Pereira, Elisabeth
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p. 2359 - 2361
(2007/10/03)
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- Oxidation of ketone by palladium(II), α-hydroxyketone synthesis catalyzed by a bimetallic palladium(II) complex
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A bimetallic palladium(II) complex containing a triketone ligand and a bridging dinitrogen ligand oxidizes ketones in aqueous THF to α-hydroxyketone by a direct air oxidation. While the normal synthesis of α-hydroxyketones involves a series of reactions, this synthesis performs the transformation in one step in a catalytic air oxidation. This synthesis does not involve an olefin and is almost unprecedented in transition metal catalysis. Its main virtue is its simplicity and actually it is an enolization reaction. Methanesulfonic acid is used to accelerate the enolization of ketones. The reaction is carried out in the presence of CuCl2 and/or dioxygen only. In particular, it is found that the hydroxyketone formation does not require the presence of CuCl2. Matrix assisted laser desorption ionization (MALDI) and time-of-flight mass spectrometry (TOFMS) are used to record the mass spectra of α-hydroxyketones products. α-Cyano-4-hydroxycinnamic acid (CHCA) matrix promoted the molecular ion detection when 180 pmol of α-hydroxyketones is introduced into the TOFMS.
- El-Qisairi, Arab K,Qaseer, Hanan A
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- Synthesis of α-acetoxy and formyloxy ketones by thallium(III) promoted α-oxidation
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Treatment of ketones with thallium(III) triflate in amide solvents at 60°C for 30 min followed by addition of small amounts of H2O cleanly provided the corresponding α-acyloxy ketones.
- Lee,Jin,Choi
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p. 956 - 957
(2007/10/03)
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- Process for the preparation of acyloins
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A process for the preparation of acyloins of the general formula I STR1 in which Ra and Rb are the same or different and stand for hydrogen or an optionally substituted C1 -C20 alkyl, an optionally substituted C
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- Selective oxidation of vinyl ethers and silyl enol ethers with hydrogen peroxide catalyzed by peroxotungstophosphate
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The oxidation of vinyl and silyl enol ethers with aqueous hydrogen peroxide was first achieved by the use of peroxotungstophosphate (PCWP) as the catalyst. For example, the oxidation of 1-ethoxy-1-octene with a stoichiometric amount of 35% H2O2 in the presence of PCWP (0.5 mol %) in a mixed solvent of methanol and dichloromethane at room temperature gave 1- ethoxy-1-methoxy-2-hydroxyoctane, a synthetic equivalent of 2- hydroxyoctanal, in 70% yield. The oxidation of acyclic silyl enol ethers such as 1-[(trimethylsilyl)oxy]-1-octene under these conditions gave 1-hydroxy-2- octanone in 725 yield, while the same oxidation in dichloromethane alone resulted in cleavage of the enol double bond to form heptanal in 71% yield. Cyclic silyl enol ethers were converted into the corresponding α-hydroxy ketones in 48-71% yields under similar reaction conditions.
- Yamamoto, Hiroyo,Tsuda, Masaya,Sakaguchi, Satoshi,Ishii, Yasutaka
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p. 7174 - 7177
(2007/10/03)
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- Oxidation reactions catalysed by titanium- and chromium-containing silicalites
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While the titanium silicalite-1 (TS-1)-tert-butyl hydroperoxide (TBHP) combination exhibits remarkable activity and selectivity in the oxidative cleavage of the C-C double bond of silyl enol ethers to produce dicarboxylic acids, the chemoselective oxidation of thioethers to sulfoxides without generation of sulfones is achieved using chromium silicalite-2 (CrS-2)-H2O2.
- Raju, Satya V. N.,Upadhya,Ponrathnam,Daniel,Sudalai
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p. 1969 - 1970
(2007/10/03)
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- Ion exchange resin-mediated hydrolytic cleavage of α-nitroepoxides. Simple one-pot synthesis of α-hydroxyketones
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α-Nitroepoxides are cleaved in an aqueous suspension with dowex-50 to furnish α-hydroxyketones in excellent yields.
- Chakraborty,Das,Ranu
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p. 1523 - 1528
(2007/10/02)
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- α-Hydroxylation on Ketones Using o-Iodosylbenzoic Acid
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o-Iodosylbenzoic acid (KOH/CH3OH) converts various ketones to α-hydroxydimethylacetals in high yield with the advantageous feature of solubility of the reduction product o-iodobenzoic acid under the basic reaction conditions thus allowing isolation of the oxidation product by simple CH2Cl2 extraction.
- Moriarty, Robert M.,Hou, Kwang-Chung
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p. 691 - 694
(2007/10/02)
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- Sensitized Photooxygenation of Silyl Enol Ethers of Cyclic Ketones
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α,β-Unsaturated and α-hydroxy ketones are accessible in prototropic ene-reactions with singlet oxygen by sensitized photooxygenation of cyclic silyl enol ethers and subsequent reduction and solvolysis.In a competing silatropic ene-reaction α-silyloxyketones are formed.Formation of different products depends on ring size, configuration and substitution.At C-6 chirally substituted 2-cyclohexenones are synthesized for the first time by sensitized photooxygenation of chiral silyl enol ethers of optically active starting ketones.
- Friedrich, Edgar,Lutz, Werner
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p. 1245 - 1263
(2007/10/02)
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