- Electrochemical synthesis of α-hydroxycarboxylic acids from acetophenones
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α-Hydroxy carboxylic acids are synthesized in 80-86% isolated yields by electrochemical carboxylation of methyl aryl ketones in the presence of carbon dioxide (1 atm.) using a platinum cathode and a sacrificial magnesium anode at a constant current density of 10 mA/cm2. Reversibility of the carbonyl group reduction and generation of anionic radical were shown by cyclic voltammetry. Copyright Taylor & Francis LLC.
- Khaja Lateef,Ramesh Raju,Krishna Mohan,Jayarama Reddy
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- Synthesis of α-hydroxycarboxylic acids from various aldehydes and ketones by direct electrocarboxylation: A facile, efficient and atom economy protocol
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In present work, the formation of α-hydroxycarboxylic acids have been described from various aromatic aldehydes and ketones via direct electrocarboxylation method with 80-92% of yield without any side product and can be purified by simple recrystallization using sacrificial Mg anode and Pt cathode in an undivided cell, CO2at (1 atm) was continuously bubbled in the cell throughout the reaction using tetrapropylammonium chloride as a supporting electrolyte in acetonitrile. The synthesized compounds obtained in fair to excellent yield with a high level of purity. The characterization of electrocarboxylated compounds was done with spectroscopic techniques like IR, NMR (1H & 13C), mass and elemental analysis.
- Singh, Kishanpal,Sohal, Harvinder Singh,Singh, Baljit
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p. 839 - 845
(2021/04/09)
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- Isothiourea-Catalyzed Acylative Kinetic Resolution of Tertiary α-Hydroxy Esters
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A highly enantioselective isothiourea-catalyzed acylative kinetic resolution (KR) of acyclic tertiary alcohols has been developed. Selectivity factors of up to 200 were achieved for the KR of tertiary alcohols bearing an adjacent ester substituent, with both reaction conversion and enantioselectivity found to be sensitive to the steric and electronic environment at the stereogenic tertiary carbinol centre. For more sterically congested alcohols, the use of a recently-developed isoselenourea catalyst was optimal, with equivalent enantioselectivity but higher conversion achieved in comparison to the isothiourea HyperBTM. Diastereomeric acylation transition state models are proposed to rationalize the origins of enantiodiscrimination in this process. This KR procedure was also translated to a continuous-flow process using a polymer-supported variant of the catalyst.
- Greenhalgh, Mark D.,Laina-Martín, Víctor,Neyyappadath, Rifahath M.,Qu, Shen,Smith, Andrew D.,Smith, Samuel M.
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supporting information
p. 16572 - 16578
(2020/09/09)
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- A Bifunctional Iron Nanocomposite Catalyst for Efficient Oxidation of Alkenes to Ketones and 1,2-Diketones
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We herein report the fabrication of a bifunctional iron nanocomposite catalyst, in which two catalytically active sites of Fe-Nx and Fe phosphate, as oxidation and Lewis acid sites, were simultaneously integrated into a hierarchical N,P-dual doped porous carbon. As a bifunctional catalyst, it exhibited high efficiency for direct oxidative cleavage of alkenes into ketones or their oxidation into 1,2-diketones with a broad substrate scope and high functional group tolerance using TBHP as the oxidant in water under mild reaction conditions. Furthermore, it could be easily recovered for successive recycling without appreciable loss of activity. Mechanistic studies disclose that the direct oxidation of alkenes proceeds via the formation of an epoxide as intermediate followed by either acid-catalyzed Meinwald rearrangement to give ketones with one carbon shorter or nucleophilic ring-opening to generate 1,2-diketones in a cascade manner. This study not only opens up a fancy pathway in the rational design of Fe-N-C catalysts but also offers a simple and efficient method for accessing industrially important ketones and 1,2-diketones from alkenes in a cost-effective and environmentally benign fashion.
- Ma, Zhiming,Ren, Peng,Song, Tao,Xiao, Jianliang,Yang, Yong,Yuan, Youzhu
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p. 4617 - 4629
(2020/05/19)
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- An efficient synthetic approach towards fully functionalized tetronic acids: The use of 1,3-dioxolane-2,4-diones as novel protected-activated synthons of α-hydroxy acids
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A new strategy for the synthesis of tetronic acids with control over the regioselective introduction of substituents at the C-5 position has been developed. The construction of the densely functionalized quaternary carbon center within these molecules is of great importance. The key element for the proposed protocol was the utilization of O-carboxyanhydrides (OCA's) of optically active α-hydroxy acids, as promising bidentate protective/activating precursors. The structure of the new compounds was investigated by using NMR spectral data and X-ray structural analyses.
- Prousis, Kyriakos C.,Markopoulos, John,Mckee, Vickie,Igglessi-Markopoulou, Olga
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p. 8637 - 8648
(2015/10/19)
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- HEPATITIS C VIRUS INHIBITORS
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The present disclosure relates to compounds, compositions and methods for the treatment of hepatitis C virus (HCV) infection. Also disclosed are pharmaceutical compositions containing such compounds and methods for using these compounds in the treatment of HCV infection.
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Page/Page column 130
(2010/12/26)
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- Evaluation of dalbavancin as chiral selector for HPLC and comparison with teicoplanin-based chiral stationary phases
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Dalbavancin is a new compound of the macrocyclic glycopeptide family. It was covalently linked to 5 lm silica particles using two different binding chemistries. Approximately 250 racemates including (a) heterocyclic compounds, (b) chiral acids, (c) chiral amines, (d) chiral alcohols, (e) chiral sulfoxides and sulfilimines, (f) amino acids and amino acid derivatives, and (g) other chiral compounds were tested on the two new chiral stationary phases (CSPs) using three different mobile phases. As dalbavancin is structurally related to teicoplanin, the same set of chiral compounds was screened on two commercially available teicoplanin CSPs for comparison. The dalbavancin CSPs were able to separate some enantiomers that were not separated by the teicoplanin CSPs and also showed improved separations for many racemates. However, there were other compounds only separated or better separated on teicoplanin CSPs. Therefore, the dalbavancin CSPs are complementary to the teicoplanin CSPs.
- Zhang, Xiaotong,Bao, Ye,Huang, Ke,Barnett-Rundlett, Kimber L.,Armstrong, Daniel W.
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experimental part
p. 495 - 513
(2010/08/20)
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- Ag-TiO2/clay composite photocatalyst for the oxidation-cyclization of 1,2-diamine compounds with propylene glycol or alcohols
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Silver-loaded TiO2 (Ag-TiO2) and acidic clay (K10 montmorillonite) composite photocatalyst has been successfully applied for the light-induced conversion of o-phenylenediamine (OPD) and its derivatives to substituted benzimidazoles with various alcohols in acetonitrile using UV-A and solar light. The influence of the various photocatalysts, solvents, and substituents on the yield and selectivity of the products has been investigated. The mechanism of photocatalysis is proposed. Loading silver on TiO2 enhances product yield and selectivity both in UV and solar light. In the presence of primary alcohols, 2-aminothiophenol forms only disulfide and hence Ag-TiO2/ clay can be used as a green catalyst for the synthesis of disulfides.
- Selvam, Kaliyamoorthy,Annadhasan, Mari,Velmurugan, Rengasamy,Swaminathan, Meenakshisundaram
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experimental part
p. 831 - 837
(2010/09/06)
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- Facile one-pot preparation of 2-arylpropionic and arylacetic acids from cyanohydrins by treatment with aqueous HI
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A novel one-pot two-step procedure has been developed to synthesize highly substituted 2-arylpropionic and arylacetic acids, by treatment with aqueous HI, from cyanohydrins. The hydrogenolytic reduction of α-hydroxy-2-arylpropionic acids was the key step of the process and the optimization of the reaction conditions led to identify aqueous HI as an appropriate and selective reagent for the reductive deoxygenation of cyanohydrins. The synthetic route described a general and efficient strategy for the preparation of large libraries of phenylacetic and phenylpropionic acids derivatives.
- Aramini, Andrea,Sablone, Manolo R.,Bianchini, Gianluca,Amore, Alessia,Fanì, Michela,Perrone, Plinio,Dolce, Alberto,Allegretti, Marcello
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experimental part
p. 2015 - 2021
(2009/07/04)
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- A general synthesis of 2-alkoxy-2-phenylpropanoic acids
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A preparation of a variety of 2-alkoxy-2-phenylpropanoic acids in two steps is described. Epoxidation of α-methylstyrene with mCPBA in methanol or primary alcohol solvents proceeded with an acid-catalyzed in situ ring opening reaction to give the corresponding 2-alkoxy-2-phenyl-1-propanols in 28-91% yield. Lower yields were realized with secondary (22-58%) and tertiary (14%) alcohols. These alcohols were cleanly oxidized to the corresponding carboxylic acids using a mild Heyns' oxidation (O2, Pt/C) in generally good to excellent yields (25-92%). The derived (S)-α-methylbenzylamide diastereomers are nearly all well separated by capillary GC, and the use of this method to determine the enantiomeric purity of brucine-resolved 2-methoxy-2-phenylpropanoic acid was demonstrated.
- Monk, Keith A.,Duncan, Nathan C.,Bauch, Eric A.,Garner, Charles M.
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p. 8605 - 8609
(2008/12/21)
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- The epimetallation and carbonation of carbonyl and imino derivatives: Epivanadation route to 2-amino and 2-hydroxy acids
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The feasibility of hydrocarboxylating carbonyl and imino derivatives by the two-step process of epimetallation and carbonation has been demonstrated with the model substrates of 9-fluorenone and 9-fluorenone anil. With lithium vanadium dihydride as the epimetallating agent, such hydrocarboxylation has led to a 75% yield of 9-hydroxy-9-fluorenecarboxylic acid and a 65% yield of 9-(N-phenylamino)-9-fluorenecarboxylic acid, respectively. Some initial success in extending the scope of this reaction to other substrates, such as benzophenone, has been achieved by using other epimetallating agents, like the presumed LiV(CH3)2 and Ti(OPri)2. A brief review of the processes and organic synthetic applications of epimetallation and transfer epimetallation of C-C π-bonds is offered as background.
- Eisch, John J.,Fregene, Paul O.,Gitua, John N.
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p. 4647 - 4653
(2008/03/12)
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- Process for producing a polyester
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A process for producing a polyester, the process comprising the steps of (1) fermenting a saccharide with a microorganism to obtain at least one substituted α-hydroxy acid represented by the formula: HO—CHR—COOH (wherein R represents a hydrocarbon group having 1 to 10 carbon atoms), and (2) polymerizing the substituted α-hydroxy acid or a derivative thereof.
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- Enhancing selectivity in oxidation catalysis with sol-gel nanocomposites
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Valuable organic compounds such as α-hydroxy acids are easily synthesised with relevant selectivity enhancement using a sol-gel hydrophobized nanostructured silica matrix doped with the organocatalyst TEMPO: A materials science based synthetic route which cannot be achieved via classical homogeneous synthesis. The Royal Society of Chemistry 2005.
- Gancitano, Pamela,Ciriminna, Rosaria,Testa, Maria Luisa,Fidalgo, Alexandra,Ilharco, Laura M.,Pagliaro, Mario
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p. 2389 - 2392
(2007/10/03)
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- Nucleophilic benzoylation using a mandelic acid dioxolanone as a synthetic equivalent of the benzoyl carbanion. Oxidative decarboxylation of α-hydroxyacids
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The synthesis of alkyl aryl ketones using a mandelic acid dioxolanone as a synthetic equivalent (Umpolung) of the benzoyl carbanion is reported. The methodology involves alkylation of the mandelic acid dioxolanone, hydrolysis of the dioxolanone moiety in the alkylated products and oxidative decarboxylation of the resulting α-hydroxyacids. The last step is carried out in a catalytic aerobic way using a Co (III) complex in the presence of pivalaldehyde under very mild conditions.
- Blay, Gonzalo,Fernandez, Isabel,Monje, Belen,Pedro, Jose R.
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p. 365 - 372
(2007/10/03)
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- Method and product for skin lightening
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A method and cosmetic product for lightening skin is provided, the method including wiping the skin with a cosmetic towelette. Impregnated on the towelette is an alpha-hydroxy carboxylic acid or salt thereof and a sunscreen agent.
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- Nucleophilic benzoylation using lithiated methyl mandelate as a synthetic equivalent of the benzoyl carbanion. Oxidative decarboxylation of α-hydroxyacids
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The synthesis of alkyl aryl ketones using lithiated methyl mandelate as a synthetic equivalent of the benzoyl carbanion is reported (Umpolung). The methodology involves alkylation of methyl mandelate, hydrolysis of the ester group and oxidative decarboxylation of the resulting α-hydroxyacids. The last step is carried out in a catalytic aerobic way using a Co(III) complex in the presence of pivalaldehyde under very mild and advantageous conditions. The procedure is also applied to methyl mandelates substituted on the aromatic ring.
- Blay, Gonzalo,Fernández, Isabel,Formentin, Pilar,Monje, Belén,Pedro, José R,Ruiz, Rafael
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p. 1075 - 1081
(2007/10/03)
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- Enantioselective synthesis of α-hydroxyacids through oxidation of terminal alkenes with AD-mix/TEMPO
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α-Hydroxyacids can be enantioselectively prepared by means of a two- step oxidation process, involving first the asymmetric dihydroxylation of a terminal alkene and subsequent oxidation with TEMPO/NaOCl/NaClO2 in good to excellent yields. No fragmentation of the glycol intermediate was detected. (C) 2000 Elsevier Science Ltd.
- Javier Aladro,Guerra, Francisco M.,Javier Moreno-Dorado,Bustamante, Jesús M.,Jorge, Zacarías D.,Massanet, Guillermo M.
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p. 3209 - 3213
(2007/10/03)
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- A convenient one-pot synthesis of quaternary α-methoxy- and α- hydroxycarboxylic acids
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Several α-methoxy- and α-hydroxycarboxylic acids have been synthesized by a new one-pot synthesis using ketones, tribromomethane, and potassium hydroxide in methanol and water, respectively, in good yields.
- Yabuuchi, Tetsuya,Kusumi, Takenori
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p. 684 - 686
(2007/10/03)
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- Catalytic aerobic oxidative decarboxylation of α-hydroxy-acids. Methyl mandelate as a benzoyl anion equivalent
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The monomeric square-planar cobalt(III) complex of bis-N,N'- disubstituted oxamides catalyses the oxidative decarboxylation of α-hydroxy acids with molecular oxygen/pivalaldehyde with very good yields. This reaction offers an interesting alternative in the use of methyl mandelate as a convenient benzoyl anion equivalent.
- Blay, Gonzalo,Fernandez, Isabel,Formentin, Pilar,Pedro, Jose R.,Rosello, Antonio L.,Ruiz, Rafael,Journaux, Yves
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p. 3327 - 3330
(2007/10/03)
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- Visible-light induced photofixation of carbon dioxide into aromatic ketones and benzyl halides catalysed by CdS nanocrystallites
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Photocatalytic fixation of CO2 into organic substrates was carried out in a CO2-saturated DMF (N,N-dimethylformamide) solution using CdS nanocrystallites prepared in DMF (CdS-DMF, mean diameter = 4 nm, hexagonal) as a photocatalyst under visible light irradiation (λ > 400 nm). Benzilic acid (BpCO2H), atrolactic acid [methyl(phenyl)glycolic; ApCO2H] and phenylacetic acid (BnCO2H) were produced from benzophenone, acetophenone and benzyl halides such as benzyl bromide (BnBr) and benzyl chloride (BnCl), respectively. The formation of CO2 anion radical (CO2.-) was confirmed by EPR spectroscopic measurements by using 5,5-dimethyl-3,4-dihydropyrrole N-oxide (DMPO) as a spin trapping agent. Both the formation of CO2.- and the concurrent one-electron reduction of the organic substrates were indispensable in the photofixation process, which suggests that the photofixation proceeds via their bimolecular coupling on the surface of CdS nanocrystallites.
- Fujiwara, Hiroaki,Kanemoto, Masashi,Ankyu, Hirofumi,Murakoshi, Kei,Wada, Yuji,Yanagida, Shozo
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p. 317 - 321
(2007/10/03)
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- CYCLIC RENIN INHIBITORS CONTAINING 3(S)-AMINO-4-CYCLOHEXYL-2(R)-HYDROXY-BUTANOIC ACID OR 4-CYCLO-HEXYL-(2R,3S)-DIHYDROXYBUTANOIC ACID OR RELATED ANALOGS
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Compounds of the formula: STR1 are disclosed. These compounds inhibit the angiotensinogen-cleaving action of the natural proteolytic enzyme, renin, and are useful in treating, preventing or managing renin-associated hypertension, hyperaldosteronism, congestive heart failure, and glaucoma.
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- A new method for the preparation of 2-aryl propionic acids using low-valent titanium
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The addition of dihalocarbenes to arylmethylketones in the presence of low-valent titanium yields 2-aryl propionic acids in acceptable yield by one pot reaction. The reaction conditions were optimized. The TiCl4/LiAlH4 ratio is one variable that controls the selectivity of the process.
- Garcia, Mariano,Del Campo, Carmen,Sinisterra, Jose V.,Llama, Emilio F.
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p. 7973 - 7974
(2007/10/02)
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- Chemoenzymatic synthesis of pure enantiomeric 2-aryl propionic acids
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A new chemoenzymatic procedure to obtain pure enantiomeric 2-arylpropionic acids is described. The one pot synthesis of (±)-2-arylpropionic acids is carried out by addition of dichlorocarbene to the C=O bond of arylmethylketones and hydrogenolysis of the additon product. The racemic mixture is resolved by enantiospecific hydrolysis of the racemic ethyl esters using native lipase from Candida rugosa. The good yields, the accessibility of the starting arylmethylketones and the stereospecificity of the enzymatic hydrolysis make the process interesting in order to obtain the same non steroidal antiinflammatory drugs such as Ibuprofen or Naproxen.
- Garcia,Del Campo,Llama,Sanchez-Montero,Sinisterra
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p. 8433 - 8440
(2007/10/02)
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- Dihydroxyacids from the chlorination of ketones: an unexpected process
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Chlorination of propiophenone in aqueous alkali at room temperature, with low concentrations of hypochlorite, leads to 2-phenylglyceric acid as the major product.This acid is formed by further oxidation of 1-phenyl-1,2-propanedione, which is an intermediate in the oxidation of propiophenone.Formation of this acid is reasonable in the light of other halogenation chemistry.Analogous reactions are observed for butyrophenone, which yields 2,3-dihydroxy-2-phenylbutanoic acid, and for cycloheptanone, which yields 1,2-dihydroxycyclohexanecarboxylic acid. Key words: 2-phenyl glyceric acid, propiophenone, chlorination, hydrolysis, rearrangement, cycloheptanone, 1,2-dihydroxycyclohexanecarboxylic acid.
- Guthrie, J. Peter,Cossar, John,Lu, Jinqiao
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p. 1904 - 1908
(2007/10/02)
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- Electrocarboxylation de composes carbonyles aliphatiques, aromatiques et vinyliques: interet de l'utilisation d'une anode consommable en magnesium
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In the presence of carbon dioxide in DMF, the electroreduction of carbonyl compounds or α,β-ketoalkenes at high concentration yields respectively α-hydroxyacids and β-ketoacids.The use of a sacrificial magnesium anode allows constant current electrolyses in a diaphragmless cell.
- Mcharek, Slah,Heintz, Monique,Troupel, Michel,Perichon, Jacques
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- Direct Optical Resolution of Carboxylic Acids by Chyral HPLC on Tris(3,5-dimethylphenylcarbamate)s of Cellulose and Amylose
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A variety of racemic carboxylic acids have been for the first time directly resolved by normal-phase, high-performance liquid chromatography using a hexane-2-propanol eluting system containing a small amount (ca. 1percent) of a strong carboxylic acid, like formic acid, trichloroacetic acid, and trifluoroacetic acid.
- Okamoto, Yoshio,Aburatani, Ryo,Kaida, Yuriko,Hatada, Koichi
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p. 1125 - 1128
(2007/10/02)
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- The synthesis of anilines or azoxybenzenes from the reduction of nitrobenzenes in basic alcoholic media
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Reduction of substituted nitrobenzenes in alkaline alcoholic solutions affords, depending on the experimental conditions used, either anilines or azoxybenzenes in good yields.In the presence of a methylketone, such as acetophenone, the reaction of nitroarenes with aqueous KOH in 2-propanol provides the corresponding anilines in high yields (80-90 percent).On the other hand, when the reaction is carried out in the CH3OH/toluene/KOH system, in the absence of methylketones, the azoxyderivatives are isolated in 70-90 percent yield.
- Prato, Maurizio,Quintily, Ugo,Scapol, Lucia,Scorrano, Gianfranco
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- Process for preparing α-hydroxy-alkanoic acids and compounds obtained by this process
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The invention relates to a process for preparing α-hydroxy-alkanoic acids of general formula: STR1 in which R represents hydrogen or a lower alkyl radical and Cy represents phenyl or a heterocyclic radical, both radicals optionally comprising one or more substituents selected from the group consisting of lower alkyl, lower alkenyl, lower alkynyl radicals and halogen atoms, process which comprises the treatment of an α,α-dihalogenated ketone of general formula: STR2 in which R and Cy have the same meaning as above and X represents chlorine, bromine or iodine, in the presence of an aqueous solution of an alkali metal hydroxide and a non polar organic solvent selected from an aromatic or alicyclic hydrocarbon, the treatment being carried out at a temperature between the boiling temperature of the reaction medium at atmospheric pressure and 240° C. under pressure and the alkali metal so formed is then acidified to obtain the desired acid.
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- ELECTROCHEMICAL CARBOXYLATION OF ALDEHYDES AND KETONES WITH SACRIFICIAL ALUMINUM ANODES.
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The electrocarboxylation of aldehydes to the corresponding α-hydroxyacids was described as impossible with conventional electrochemical systems.It is reported here that it is possible to realize it in diaphragmless cells making use of sacrificial aluminum anodes.The method can be used also for the electrocarboxylation of ketones with good yields.
- Silvestri, G.,Sambino, S.,Filardo, G.
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p. 3429 - 3430
(2007/10/02)
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- Optical Resolution of 2-Amino-1,2-diphenylethanol by Preferential Crystallization and Its Utilization in Fractional Crystallization and Enantioselective Reduction of Prochiral Ketones
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(-/+)-erythro-2-Amino-1,2-diphenylethanol prepared from benzoin oxime by catalytic reduction was successfully resolved into pair of optically active forms by preferential crystallization.The optically active amino alcohol was found to be useful as a basic resolving agent for optical resolution of tartaric acid, trans-2,3-oxiranedicarboxylic acid, 2-hydroxy-2-phenylpropionic acid, and 3-endo-benzamido-5-norbornene-2-endo-carboxylic acid.Chiral hydrides prepared from lithium aluminium hydride and optical active threo- and erythro-2-amino-1,2-diphenylethanol derivatives were applied to the enantioface differentiating reduction of prochiral ketones to give the corresponding optically active alcohols in the 26-72percent optical purities.
- Saigo, Kazuhiko,Ogawa, Shigeo,Kikuchi, Shigetoshi,Kasahara, Atsushi,Nohira, Hiroyuki
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p. 1568 - 1573
(2007/10/02)
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- Preferential Cryatallization of 2-Amino-2-phenylethanol and Its Application as a Resolving Agent
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(+/-)-2-Amino-2-phenylethanol (phenylglycinol) prepared from (+/-)-2-amino-2-phenylacetic acid (DL-phenylglycine) by lithium aluminium hydride reduction was efficiently resolved into a pair of optically active forms by preferential crystallization.The optically active amino alcohol was successfully applied as a basic resolving agent to the resolution of tartaric acid, 2-hydroxy-2-phenylpropionic acid, 2-hydroxy-3-phenylpropionic acid, 2-phenylpropionic acid, and 2-phenyl-2-ureidoacetic acid.
- Saigo, Kazuhiko,Miura, Hisao,Ishizaki, Kozi,Nohira, Hiroyuki
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p. 1188 - 1190
(2007/10/02)
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- Asymmetric Addition of Organometallics to Chiral Ketooxazolines. Preparation of Enantiomerically Enriched α-Hydroxy Acids
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Addition of Grignard and organolithium reagents to chiral α-ketooxazolines results in α-substituted α-hydroxyoxazoline derivatives which on hydrolytic removal of the chiral auxiliary groups give rise to α-substituted α-hydroxy acids in 30-87 percent enantiomeric excess (ee).Studies on the various parameters (solvents, temperature, substituents) were undertaken to reach optimum asymmetric induction.
- Meyers, A. I.,Slade, Joel
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p. 2785 - 2791
(2007/10/02)
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