- Photocatalytic Hydromethylation and Hydroalkylation of Olefins Enabled by Titanium Dioxide Mediated Decarboxylation
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A versatile method for the hydromethylation and hydroalkylation of alkenes at room temperature is achieved by using the photooxidative redox capacity of the valence band of anatase titanium dioxide (TiO2). Mechanistic studies support a radical-based mechanism involving the photoexcitation of TiO2 with 390 nm light in the presence of acetic acid and other carboxylic acids to generate methyl and alkyl radicals, respectively, without the need for stoichiometric base. This protocol is accepting of a broad scope of alkene and carboxylic acids, including challenging ones that produce highly reactive primary alkyl radicals and those containing functional groups that are susceptible to nucleophilic substitution such as alkyl halides. This methodology highlights the utility of using heterogeneous semiconductor photocatalysts such as TiO2 for promoting challenging organic syntheses that rely on highly reactive intermediates.
- Zhu, Qilei,Nocera, Daniel G.
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supporting information
p. 17913 - 17918
(2020/12/04)
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- Achiral Derivatives of Hydroxamate AR-42 Potently Inhibit Class i HDAC Enzymes and Cancer Cell Proliferation
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AR-42 is an orally active inhibitor of histone deacetylases (HDACs) in clinical trials for multiple myeloma, leukemia, and lymphoma. It has few hydrogen bond donors and acceptors but is a chiral 2-arylbutyrate and potentially prone to racemization. We report achiral AR-42 analogues incorporating a cycloalkyl group linked via a quaternary carbon atom, with up to 40-fold increased potency against human class I HDACs (e.g., JT86, IC50 0.7 nM, HDAC1), 25-fold increased cytotoxicity against five human cancer cell lines, and up to 70-fold less toxicity in normal human cells. JT86 was ninefold more potent than racAR-42 in promoting accumulation of acetylated histone H4 in MM96L melanoma cells. Molecular modeling and structure-activity relationships support binding to HDAC1 with tetrahydropyran acting as a hydrophobic shield from water at the enzyme surface. Such potent inhibitors of class I HDACs may show benefits in diseases (cancers, parasitic infections, inflammatory conditions) where AR-42 is active.
- Tng, Jiahui,Lim, Junxian,Wu, Kai-Chen,Lucke, Andrew J.,Xu, Weijun,Reid, Robert C.,Fairlie, David P.
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supporting information
p. 5956 - 5971
(2020/06/05)
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- Impact of variation of the acyl group on the efficiency and selectivity of the lipase-mediated resolution of 2-phenylalkanols
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By tuning the steric properties of the acyl group to control the efficiency and selectivity of the resolution, 2-phenyl-1-propanol 1a was prepared by lipase-catalysed hydrolysis using a short-chain acyl group, with E-values of up to 66 (ee up to 95%). 2-Phenylbutan-1-ol 1b was similarly resolved (up to 86% ee) using the optimised conditions, while the ester of the more sterically demanding 3-methyl-2-phenylbutan-1-ol 1c proved resistant to enzymatic hydrolysis under these conditions.
- Foley, Aoife M.,Gavin, Declan P.,Joniec, Ilona,Maguire, Anita R.
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p. 1144 - 1153
(2017/09/15)
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- Stereoselective Ketone Rearrangements with Hypervalent Iodine Reagents
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The first stereoselective version of an iodine(III)-mediated rearrangement of arylketones in the presence of orthoesters is described. The reaction products, α-arylated esters, are very useful intermediates in the synthesis of bioactive compounds such as ibuprofen. With chiral lactic acid-based iodine(III) reagents product selectivities of up to 73 % ee have been achieved.
- Malmedy, Florence,Wirth, Thomas
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supporting information
p. 16072 - 16077
(2016/10/30)
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- Continuous in situ electrogenaration of a 2-pyrrolidone anion in a microreactor: application to highly efficient monoalkylation of methyl phenylacetate
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We have successfully demonstrated effective generation of an electrogenerated base (EGB) such as the 2-pyrrolidone anion and its rapid use for the following alkylation reaction in a flow microreactor system without the need for severe reaction conditions. The key feature of the method is effective and selective preparation of monoalkylated products.
- Matsumura, Yoshimasa,Kakizaki, Yoshinobu,Tateno, Hiroyuki,Kashiwagi, Tsuneo,Yamaji, Yoshiyuki,Atobe, Mahito
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p. 96851 - 96854
(2015/11/24)
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- Synthesis of α-aryl esters and nitriles: Deaminative coupling of α-aminoesters and α-aminoacetonitriles with arylboronic acids
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Transition-metal-free synthesis of α-aryl esters and nitriles using arylboronic acids with α-aminoesters and α-aminoacetonitriles, respectively, as the starting materials has been developed. The reaction represents a rare case of converting C(sp3)-N bonds into C(sp3)-C(sp2) bonds. The reaction conditions are mild, demonstrate good functional-group tolerance, and can be scaled up. Touch base: A transition-metal-free protocol for the synthesis of α-aryl esters and nitriles by deaminative coupling is presented. Strong bases and transition-metal catalysts are not needed. The new synthetic method uses readily available starting materials and demonstrates wide substrate scope.
- Wu, Guojiao,Deng, Yifan,Wu, Chaoqiang,Zhang, Yan,Wang, Jianbo
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supporting information
p. 10510 - 10514
(2016/02/18)
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- PDE10 INHIBITORS AND RELATED COMPOSITIONS AND METHODS
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Compounds that inhibit PDE10 are disclosed that have utility in the treatment of a variety of conditions, including (but not limited to) psychotic, anxiety, movement disorders and/or neurological disorders such as Parkinson's disease, Huntington's disease, Alzheimer's disease, encephalitis, phobias, epilepsy, aphasia, Bell's palsy, cerebral palsy, sleep disorders, pain, Tourette's syndrome, schizophrenia, delusional disorders, drug-induced psychosis and panic and obsessive-compulsive disorders. Pharmaceutically acceptable salts, stereoisomers, solvates and prodrugs of the compounds are also provided. Also disclosed are compositions containing a compound in combination with a pharmaceutically acceptable carrier, as well as methods relating to the use thereof for inhibiting PDE10 in a warm-blooded animal in need of the same.
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Page/Page column 17
(2010/03/02)
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- Synthesis of 3,3-and 4,4-alkyl-phenyl-substituted pyrrolidin-2-one derivatives
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Syntheses of 3,3-and 4,4-alkyl-phenyl-substituted pyrrolidin-2-one derivatives are described. The final compounds were obtained by the reductive cyclization of relevant cyanoalkanoate esters using NaBH4 and CoCl2.6H2O. The obtained pyrroIidin-2-one derivatives are pharmacophoric fragments for the synthesis of various biologically active compounds.
- Kulig,Ignasik,Malawska
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experimental part
p. 1629 - 1636
(2010/07/06)
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- Arylation and vinylation of α-diazocarbonyl compounds with boroxines
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An alternative approach for α-arylation and α-vinylation of carbonyl compounds is described: reaction between aryl-or vinylboroxines with α-diazocarbonyl compounds leads to the formation of α-arylated or α-vinylated carbonyl compounds under mild conditions.
- Peng, Cheng,Zhang, Wei,Yan, Guobing,Wang, Jianbo
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supporting information; experimental part
p. 1667 - 1670
(2009/08/07)
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- Oxidative rearrangements of arylalkanones with 1H-1-hydroxy-5-methyl-1,2,3-benziodoxathiole 3,3-dioxide, a 'green' analog of Koser's reagent
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Previous methods for the conversion of arylalkanones to alkyl 2-arylesters by oxidative rearrangement utilized reagents which either produced toxic metal salts or halogenated organics as by-products. In this report, 1H-1-hydroxy-5-methyl-1,2,3-benziodoxathiole 3,3-dioxide (HMBI) is used to effect this useful transformation, where the reduced iodine reagent is water-soluble and readily recycled.
- Justik, Michael W.
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p. 3003 - 3007
(2008/02/06)
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- Enecarbamates as Selective Substrates in Oxidations: Chiral-Auxiliary-Controlled Mode Selectivity and Diastereoselectivity in the [2+2] Cycloaddition and Ene Reaction of Singlet Oxygen and in the Epoxidation by DMD and mCPBA
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The stereochemical course of the oxidation of chiral oxazolidinone-substituted enecarbamates has been studied for singlet oxygen (1O2), dimethyldioxirane (DMD), and m-chloroperbenzoic acid (mCPBA) by examining of the special structural and stereoelectronic features of the enecarbamates. Valuable mechanistic insight into these selective oxidations is gained. Whereas the R1 substituent on the chiral auxiliary is responsible for the steric shielding of the double bond and determines the sense of the π-facial diastereoselectivity, structural characteristic such as the Z/E configuration and the nature of the R 2 group on the double bond are responsible for the extent of the diastereoselectivity. Stereoelectronic steering by the vinylic nitrogen functionality controls the mode selectivity (ene reaction vs [2+2] cycloaddition) in the case of 1O2.
- Adam, Waldemar,Bosio, Sara G.,Turro, Nicholas J.,Wolff, Barbara T.
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p. 1704 - 1715
(2007/10/03)
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- Enantioselective synthesis of allenecarboxylates from phenyl acetates through C-C bond forming reactions
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A variety of optically active 4,4-disubstituted allenecarboxylic acid methyl esters were prepared from simple α,α-disubstituted phenyl acetate through base treatment of the esters to generate ketenes, followed by successive Horner-Wadsworth-Emmons reaction. The transformation was further developed as a one-pot procedure with satisfactory yields and high enantioselectivity.
- Yamazaki, Jiro,Watanabe, Toshiyuki,Tanaka, Kiyoshi
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p. 669 - 675
(2007/10/03)
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- Novel N-substituted alpha aminoacid amides as calcium channel modulators
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The compounds of formula I and derivatives thereof have been found to be active in tests that show modulation of voltage-dependent calcium channels, and are thus indicated for use in the treatment of diseases in which such modulation is beneficial, in par
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- RENIN INHIBITING COMPOUNDS
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Compounds which are amino acid derivatives and have the formula STR1 in which R 1 is hydrogen or methyl, R 2 is ethyl, propyl or imidazol-4-yl, R 3 is isobutyl, cyclohexylmethyl or benzyl, and A is defined as herein are useful as renin inhibitors.
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