- LABDANE DERIVATIVES AND FLAVONES FROM GUTIERREZIA DRACUNCULOIDES
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Key Word Index - Guiterrezia dracunculoids; Compositae; new labdane derivatives; new flavones. An investigation of the aerial parts of Gutierrezia dracunculoides afforded, in addition to known compounds, three new labdan derivatives, all related to lambertianic acid, 17-hydroxy- and 17-acetoxylambertianic acid and 7α-hydroxylambertianic acid, two esterifid and tree highly oxygnated flavones, 5,7,4'-trihydroxy-3,3'-dimethoxy-flavone-4'-O- and isovalerate, 3',5'-dihydroxy-3,5,6,7,8,4'hexamethoxyflavone, 5,3',5'-trihydroxy-3,6,7,8,4'-pentamethoxyflavone and 5,7,3'5'-tetrahydroxy-3,6,8,4-tetramethoxyflavone.The structures were elucidated by spectroscopic methods and a few chemical transformations.
- Bohlmann, Ferdinand,Grenz, Michael,Dahr, Autar K.,Goodman, Mark
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Read Online
- The degradation mechanism of toxic atractyloside in herbal medicines by decoction
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Atractyloside (ATR) is found in many Asteraceae plants that are commonly used as medicinal herbs in China and other eastern Asian countries. ATR binds specifically to the adenine nucleotide translocator in the inner mitochondrial membrane and competitively inhibits ADP and ATP transport. The toxicity of ATR in medical herbs can be reduced by hydrothermal processing, but the mechanisms of ATR degradation are not well understood. In this study, GC-MS coupled with SPE and TMS derivatisation was used to detect ATR levels in traditional Chinese medicinal herbs. Our results suggest that ATR molecules were disrupted by decomposition, hydrolysis and saponification after heating with water (decoction) for a long period of time. Hydrothermal processing could decompose the endogenous toxic compounds and also facilitate the detoxification of raw materials used in the Chinese medicine industry.
- Chen, Liang-Yu,Hu, Anren,Chang, Chih-Jui
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- Kinetics and mechanism of oxidation of L-leucine by alkaline diperiodatocuprate(III). A free radical intervention, deamination and decarboxylation
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The kinetics of oxidation of L-leucine by diperiodatocuprate (III) (DPC) in aqueous alkaline medium at a constant ionic strength of 0.10mol dm-3 was studied spectrophotometrically. The reaction between L-leucine and DPC in alkaline medium exhibits 1:4 stoichiometry (L-leucine: DPC). The reaction is of first order in [DPC] and has less than unit order in both [L-leucine] and [alkali]. However, the order in [Lleucine] and [alkali] changes from first order to zero order as their concentration increase. Intervention of free radicals was observed in the reaction. Increase in periodate concentration decreased the rate. The oxidation reaction in alkaline medium has been shown to proceed via a monoperiodatocuprate (III) - L-leucine complex, which decomposed slowly in a rate-determining step followed by other fast steps to give the products. The main oxidative products were identified by spot test and GC-MS. The reaction constants involved in the different steps of the mechanism were calculated. Indian Academy of Sciences.
- Naik, Keerti M.,Nandibewoor, Sharanappa T.
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- Acylated glycosidic acid methyl esters generated from the convolvulin fraction of Rhizoma Jalapae Braziliensis by treatment with indium(III) chloride in methanol
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Four hexaglycosides of methyl 3S,12S-dihydroxyhexadecanoate (1-4) were provided after treatment of the crude convolvulin fraction from Rhizoma Jalapae Braziliensis (the root of Ipomoea operculata (GOMES) MART., Convolvulaceae) with indium(III) chloride in
- Ono, Masateru,Oda, Satoko,Yasuda, Shin,Mineno, Tomoko,Okawa, Masafumi,Kinjo, Junei,Miyashita, Hiroyuki,Yoshimitsu, Hitoshi,Nohara, Toshihiro,Miyahara, Kazumoto
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- 2α-ISO-VALEROYLOXYEPERUIC ACID, A DITERPENE FROM EUPATORIUM PETIOLARE
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The diterpene acid 2α-iso-valeroyloxyeperuic acid was isolated from the aerial parts of Eupatorium petiolare.Its structure and stereochemistry were elucidated by spectroscopic methods and chemical correlation with eperuic acid. - Key Word Index: Eupatorium petiolare; Compositae; Eupatorieae; labdane type diterpenes; 2α-iso-valeroyloxyeperuic acid.
- Calderon, J. S.,Quijano, L.,Garduno, M.,Gomez, F.,Rios, T.
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- Transformation of Thioacids into Carboxylic Acids via a Visible-Light-Promoted Atomic Substitution Process
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A visible-light-promoted atomic substitution reaction for transforming thiocacids into carboxylic acids with dimethyl sulfoxide (DMSO) as the oxygen source has been developed, affording various alkyl and aryl carboxylic acids in over 90% yields. The atomic substitution process proceeds smoothly through the photochemical reactivity of the formed hydrogen-bonding adduct between thioacids and DMSO. A DMSO-involved proton-coupled electron transfer (PCET) and the simultaneous generation of thiyl and hydroxyl radicals are proposed to be key steps for realizing the transformation.
- Fu, Qiang,Liang, Fu-Shun,Lou, Da-Wei,Pan, Gao-Feng,Wang, Rui,Wu, Min,Xie, Kai-Jun
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supporting information
p. 2020 - 2024
(2022/03/31)
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- Method for preparing isovaleric acid, ligand and complex in catalytic system of isovaleric acid, and application of catalytic system
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The invention provides a method for preparing isovaleric acid. According to the method, in the presence of a catalytic system, isovaleraldehyde is subjected to an oxidation reaction so as to obtain isovaleric acid, wherein the catalytic system comprises a catalyst which is a complex formed by a naphthalate ligand and a palladium-containing compound, the naphthalate ligand comprises a compound witha structure as shown in a formula I which is described in the specification. In the formula I, R1-R10 are respectively and independently selected from a group consisting of -NO2, -F, -Br, -Cl, -I, -H, -CH3, -CH2CH3, -OCH3, -CH(CH3)2 and -C(CH3)3; and preferably, at least one ester group in the compound with the structure as shown in the formula I is substituted at the beta position of a naphthalene ring. The invention provides the isovaleric acid preparation method with high selectivity, high yield and high safety.
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Paragraph 0087-0111
(2020/02/29)
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- Method for producing aliphatic carboxylic acid compound and pyridine compound adduct of aliphatic ketone compound
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Provided are: a method for producing an aliphatic carboxylic acid compound safely and easily from a starting material that can be obtained or produced industrially without generating a harmful substance such as haloform; and a pyridine compound adduct of an aliphatic ketone compound. The method for producing an aliphatic carboxylic acid compound is a method for producing an aliphatic carboxylic acid compound represented by Formula (I), and comprises: a first step for obtaining a pyridine compound adduct by adding a pyridine compound to an aliphatic ketone compound having an alpha-methyl groupin the presence of an oxidizing agent; and a second step of hydrolyzing the pyridine compound adduct in the presence of a base. In the Formula, R1 represents a substituted or unsubstituted linear alkyl group having 4-8 carbon atoms or a substituted or unsubstituted branched alkyl group having 4-8 carbon atoms; M represents hydrogen, a metal belonging to Group 1 or Group 2 of the periodic table, amethyl group, an ethyl group, an n-propyl group or an isopropyl group.
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Paragraph 0172; 0175-0176; 0182; 0185-0186; 0192; 0195-0196
(2020/05/02)
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- Chemoselective Hydrogenation of α,β-Unsaturated Carbonyls Catalyzed by Biomass-Derived Cobalt Nanoparticles in Water
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Herein, we report highly chemoselective hydrogenation of α,β-unsaturated carbonyls to saturated carbonyls catalyzed by cobalt nanoparticles supported on the biomass-derived carbon from bamboo shoots with molecular hydrogen in water, which is the first prototype using a heterogeneous non-noble metal catalyst for such organic transformation as far as we know. The optimal cobalt nanocatalyst, CoOx@NC-800, manifested remarkable activity and selectivity for hydrogenation of C=C in α,β-unsaturated carbonyls under mild conditions. A broad set of α,β-aromatic and aliphatic unsaturated carbonyls were selectively reduced to their corresponding saturated carbonyls in up to 99 % yields with good tolerance of various functional groups. Meanwhile, a new straightforward one-pot cascade synthesis of saturated carbonyls was realized with high activity and selectivity via the cross-aldol condensation of ketones with aldehydes followed by selective hydrogenation. More importantly, this one-pot strategy is applicable for the expedient synthesis of Loureirin A, a versatile bioactive and medicinal molecule, from readily available starting materials, further highlighting the practical utility of the catalyst. In addition, the catalyst can be easily separated for successive reuses without significant loss in both activity and selectivity.
- Song, Tao,Ma, Zhiming,Yang, Yong
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p. 1313 - 1319
(2019/01/25)
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- Synthesis of Carboxylic Acids by Palladium-Catalyzed Hydroxycarbonylation
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The synthesis of carboxylic acids is of fundamental importance in the chemical industry and the corresponding products find numerous applications for polymers, cosmetics, pharmaceuticals, agrochemicals, and other manufactured chemicals. Although hydroxycarbonylations of olefins have been known for more than 60 years, currently known catalyst systems for this transformation do not fulfill industrial requirements, for example, stability. Presented herein for the first time is an aqueous-phase protocol that allows conversion of various olefins, including sterically hindered and demanding tetra-, tri-, and 1,1-disubstituted systems, as well as terminal alkenes, into the corresponding carboxylic acids in excellent yields. The outstanding stability of the catalyst system (26 recycling runs in 32 days without measurable loss of activity), is showcased in the preparation of an industrially relevant fatty acid. Key-to-success is the use of a built-in-base ligand under acidic aqueous conditions. This catalytic system is expected to provide a basis for new cost-competitive processes for the industrial production of carboxylic acids.
- Sang, Rui,Kucmierczyk, Peter,Dühren, Ricarda,Razzaq, Rauf,Dong, Kaiwu,Liu, Jie,Franke, Robert,Jackstell, Ralf,Beller, Matthias
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supporting information
p. 14365 - 14373
(2019/09/06)
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- Flavanonol Glycosides from Leaves of Phellodendron lavallei Introduced in Georgia
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The new flavanonol glycoside (2S,3S)-3,5-dihydroxy-2-(4′-hydroxyphenyl)-8-(3-methylbut-2-en-1-yl)-4-oxo-3,4-dihydro-2H-chromen-7-yl-β-D-glucopyranosyl-(3→1)-xylopyranoside (lavaloside) (1) and the known compound phellamurin (2) were isolated from leaves o
- Shalashvili,Sutiashvili,Alaniya,Kavtaradze, N. Sh.,Skhirtladze
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p. 263 - 266
(2018/04/17)
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- Efficient and selective oxidation of aldehydes with dioxygen catalysed by vanadium-containing heteropolyanions
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The heteropolyacids “H3+n[PMo12–nVnO40]·aq” (denoted as HPA-n; n = 2, 3, 8) catalyse the oxidation of aldehydes to carboxylic acids in the presence of dioxygen with very good yields. The effect on the catalytic activity of various parameters such as the precursors, solvent, temperature or catalyst/substrate ratio was examined. The process is particularly selective for linear and aromatic aldehydes. The oxidation of adipaldehyde with dioxygen in mild conditions, in the presence of HPA-2 as a catalyst, leads to the formation of adipic acid together with a significant amount of other byproducts. Thus, several modifications of the catalytic systems have been carried out to improve their selectivity. The effect of cocatalysts was investigated and, among the species tested, complex Ni(acac)2 was found to be the most efficient yielding 60% of adipic acid.
- El Amrani, Ikram,Atlamsani, Ahmed,Dakkach, Mohamed,Rodríguez, Montserrat,Romero, Isabel,Amthiou, Souad
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p. 888 - 895
(2017/09/26)
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- Preparation method of low carbon fatty acid
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The invention discloses a preparation method of low carbon fatty acid and belongs to the field of organic synthesis technology. The preparation method comprises the following technological steps: weighing low carbon fatty alcohol, water and urea, stirring and mixing, dropwise adding hydrogen peroxide and carrying out an oxidation reaction, wherein concentration of hydrogen peroxide is 5-30%; reaction temperature is 0-50 DEG C; reaction time is 5-20 h; and molar ratio of urea to hydrogen peroxide to low carbon fatty alcohol is 0.1-1: 2-5: 1. The method for preparing low carbon fatty acid has advantages of simple operation, less environmental pollution, no corrosion to reaction equipment, high efficiency and low processing cost, and can be widely applied in the field of low carbon fatty acid preparation.
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Paragraph 0015; 0016
(2017/04/20)
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- Cp2TiCl2-catalyzed hydrocarboxylation of alkynes with CO2: formation of α,β-unsaturated carboxylic acids
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Cp2TiCl2-catalyzed hydrocarboxylation of alkynes with CO2 (atmospheric pressure) has been reported. A range of alkynes were transformed to the corresponding α,β-unsaturated carboxylic acids in high yields with high regioselectivity. The reaction proceeded with hydrotitanation, transmetalation, and subsequently carboxylation with CO2
- Shao, Peng,Wang, Sheng,Du, Gaixia,Xi, Chanjuan
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p. 3534 - 3539
(2017/01/25)
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- Cytotoxic isovaleryl sucrose esters from Ainsliaea yunnanensis: reduction of mitochondrial membrane potential and increase of reactive oxygen species levels in A549 cells
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Eight isovaleryl sucrose esters, named ainslosides A-H (1-8), were isolated from Ainsliaea yunnanensis Franch. Their structures, including the absolute configurations of the sugar residues, were elucidated by extensive analysis of NMR spectra and acid hydrolysis. All compounds were tested in vitro for cytotoxicity against four human tumour cell lines, A549, HCT116, MDA-MB-231, and BEL7404. Among the compounds tested, ainsloside B (2) showed potent cytotoxicity against the A549 cell line with an IC50 value of 3.3 μM. Flow cytometry analysis showed that compound 2 can arrest the cell cycle at the G0/G1 phase and induce cell apoptosis in A549 cells. Further studies indicated that the apoptosis-inducing effect of compound 2 may be involved in the reduction of mitochondrial membrane potential (MMP) and increase of reactive oxygen species (ROS) level in A549 cells.
- Fang, Xin,Zhuo, Zhi-Guo,Xu, Xi-Ke,Ye, Ji,Li, Hui-Liang,Shen, Yun-Heng,Zhang, Wei-Dong
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p. 20865 - 20873
(2017/04/26)
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- Preparation method of carboxylic acid compound
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The invention provides a preparation method of a carboxylic acid compound. The preparation method comprises the following step of taking a lactone component to react with hydrogen in the presence of a compound catalyst to obtain the carboxylic acid compound. The compound catalyst comprises a hydrogenation catalyst and Lewis acid. In the presence of the compound catalyst comprising the hydrogenation catalyst and the Lewis acid, the lactone component is subjected to hydrogenation ring-opening reaction to obtain the carboxylic acid compound. The preparation method has the advantages of moderate reaction conditions and high yield; compared with a traditional method, less byproducts are generated, green and chemical requirements are met and the industrial value is better.
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Paragraph 0113; 0191-0193
(2017/08/29)
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- A Comprehensive Study on Metal Triflate-Promoted Hydrogenolysis of Lactones to Carboxylic Acids: From Synthetic and Mechanistic Perspectives
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Direct hydrogenolysis of lactone to carboxylic acid (i.e., hydrogenolysis of the Calkoxy-O bond with the carbonyl group untouched) is generally difficult, as the current strategies employing Br?nsted acids as the catalyst usually require harsh conditions such as a high temperature and a high H2 pressure. Herein, we report a developed solvent-free catalytic transformation, in which W(OTf)6 is believed to promote the hydrogenolysis process. This strategy could efficiently hydrogenate lactones to carboxylic acids under extra mild conditions (e.g., a reaction temperature of 2) and showed a broad substrate scope. In addition, the catalytic protocol can be further applied to the hydrogenolysis of polyhydroxyalkanoate, as a renewable polymer, to the corresponding straight-chain carboxylic acids. An extensive mechanistic study was subsequently performed, and the density functional theory calculations revealed a reaction pattern, including the complete cleavage of the C=O bond with the assistance of the W(OTf)6 catalyst. Moreover, the key intermediate created in the mechanism, as an oxonium with an OTf moiety, was successfully detected by electrospray ionization mass spectra. Through a comparison with the Br?nsted acid-catalyzed system, the study confirmed that the existence of the OTf moiety can significantly lower the barriers associated with the rearrangement and elimination processes. Meanwhile, emphasis was placed on the critical role that the anion plays, as well as the fact that the anion effect is directly related to the chemoselectivity.
- Zhu, Rui,Jiang, Ju-Long,Li, Xing-Long,Deng, Jin,Fu, Yao
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p. 7520 - 7528
(2017/11/10)
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- Sucrose derivatives, preparation method of same, and application thereof as anti-cancer medicine
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The invention relates to the technical field of medicines, and particularly provides a series of new-structure sucrose derivatives, on which hydroxyl groups are esterified by isovaleric acid, and a preparation method of same, and an application of the sucrose derivatives in preparation of anti-cancer medicines. The sucrose derivative is separated from a Compositae Ainsliaea plant, Ainsliaea yunnanensis Franch. The chemical structure of the sucrose derivative is represented as the formula (I). The sucrose derivative has significant cytotoxic activity to human lung adenocarcinoma cell A549 and can be used for preparing anti-cancer medicines.
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Paragraph 0059-0060
(2017/12/28)
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- Transfer Hydrogenation of Nitriles, Olefins, and N-Heterocycles Catalyzed by an N-Heterocyclic Carbene-Supported Half-Sandwich Complex of Ruthenium
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In the presence of KOBut, N-heterocyclic carbene-supported half-sandwich complex [Cp(IPr)Ru(pyr)2][PF6] (3) (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) catalyzes transfer hydrogenation (TH) of nitriles, activated N-heterocycles, olefins, and conjugated olefins in isopropanol at the catalyst loading of 0.5%. The TH of nitriles leads to imines, produced as a result of coupling of the initially formed amines with acetone (produced from isopropanol), and showed good chemoselectivity. Reduction of N-heterocycles occurs for activated polycyclic substrates (e.g., quinoline) and takes place exclusively in the heterocycle. The TH also works well for linear and cyclic olefins but fails for trisubstituted substrates. However, the C = C bond of α,β-unsaturated esters, amides, and acids is easily reduced even for trisubstituted species, such as isovaleriates. Mechanistic studies suggest that the active species in these catalytic reactions is the trihydride Cp(IPr)RuH3 (5), which can catalyze these reactions in the absence of any base. Kinetic studies are consistent with a classical inner sphere hydride-based mechanism of TH.
- Mai, Van Hung,Nikonov, Georgii I.
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p. 943 - 949
(2016/05/09)
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- 1H-pyrrole-2,4-dicarbonyl-derivatives and their use as flavoring agents
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The present invention primarily relates to 1H-pyrrole-2,4-dicarbonyl-derivatives of Formula (I) wherein R1, R2, R3, Z. Z' and J are as defined in the description, to mixtures thereof and to the use thereof as flavoring agents. The compounds in accordance with the present invention are suitable for producing, imparting, or intensifying an umami flavor. The invention further relates to flavoring mixtures, compositions for oral consumption as well as ready-to-eat, ready-to-use and semifinished products, comprising an effective amount of the compound of Formula (I) or of a mixture of compounds of Formula (I) and to specific methods for producing, imparting, modifying and/or intensifying specific flavor impressions.
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- Imidazo[1,2-a]pyridine-ylmethyl-derivatives and their use as flavoring agents
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The present invention primarily relates to imidazo[1,2-a]pyridine-ylmethyl-derivatives of Formula (I) wherein R1, R2, X, W e J are as defined in the description, to mixtures thereof and to the use thereof as flavoring agents. The compounds in accordance with the present invention are suitable for producing, imparting, or intensifying an umami flavor. The invention further relates to flavoring mixtures, compositions for oral consumption as well as ready-to-eat, ready-to-use and semifinished products, comprising an effective amount of the compound of Formula (I) and to specific methods for producing, imparting, modifying and/or intensifying specific flavor impressions.
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- Alcohol cross-coupling for the kinetic resolution of diols via oxidative esterification
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We present an organocatalytic C-O-bond cross-coupling strategy to kinetically resolve racemic diols with aromatic and aliphatic alcohols, yielding enantioenriched esters. This one-pot protocol utilizes an oligopeptide multicatalyst, m-CPBA as the oxidant, and N,N-diisopropylcarbodiimide as the activating agent. Racemic acyclic diols as well as trans-cycloalkane-1,2-diols were kinetically resolved, achieving high selectivities and good yields for the products and recovered diols.
- Hofmann, Christine,Schümann, Jan M.,Schreiner, Peter R.
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p. 1972 - 1978
(2015/02/19)
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- Aerobic oxidation of aldehydes: Selectivity improvement using sequential pulse experimentation in continuous flow microreactor
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The aerobic oxidation of aldehydewas investigated using a continuous flow microreactor under 5 bar of oxygen at room temperature. High-throughput screening of experimental conditions resulted in the development of an improved protocol. The synergistic use of a large range of salts and Mn(II) catalyst was found to be a very efficient catalytic system for selective aldehyde oxidation. Indeed for short residence time (i.e. 6min.), a quantitative conversion of 2-ethylhexanal was obtained with a selectivity toward carboxylic acid of 98%.
- Vanoye, Laurent,Pablos, Mertxe,Smith, Neil,De Bellefon, Claude,Favre-Rguillon, Alain
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p. 57159 - 57163
(2015/01/09)
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- Oxidation of isohumulones induces the formation of carboxylic acids by hydrolytic cleavage
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The degradation of isohumulones in mechanistic experiments was investigated. Incubation of trans-isohumulone in the presence of l-proline led to the formation of carboxylic acids and their corresponding proline amides. In the context of isohumulones unknown amides were verified first in model incubations and then in beer for the first time by comparison with authentic reference standards via LC-MS analyses. Carboxylic acids and amides were formed preferably under oxidative conditions and increasing pH. Stable isotope experiments excluded the incorporation of molecular oxygen into carboxylic acids, strongly indicating a hydrolytic mechanism via β-dicarbonyl cleavage. The proposed mechanism includes oxidation and thereby incorporation of molecular oxygen to the isohumulone ring structure followed by hydrolytic cleavage leading to acids and amides.
- Rakete, Stefan,Berger, Robert,Boehme, Steffi,Glomb, Marcus A.
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p. 7541 - 7549
(2014/08/18)
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- Metal-free, hydroacylation of CC and NN bonds via aerobic C-H activation of aldehydes, and reaction of the products thereof
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In this report, a thorough evaluation of the use of aerobically initiated, metal-free hydroacylation of various CC and NN acceptor molecules with a wide range of aldehydes is presented. The aerobic-activation conditions that have been developed are in sharp contrast to previous conditions for hydroacylation, which tend to use transition metals, peroxides that require thermal or photochemical degradation, or N-heterocyclic carbenes. The mildness of the conditions enables a number of reactions involving sensitive reaction partners and, perhaps most significantly, allows for α-functionalised chiral aldehydes to undergo radical-based hydroacylation with complete retention of optical purity. We also demonstrate how the resulting hydroacylation products can be transformed into other useful intermediates, such as γ-keto- sulfonamides, sultams, sultones, cyclic N-sulfonyl imines and amides.
- Chudasama, Vijay,Akhbar, Ahmed R.,Bahou, Karim A.,Fitzmaurice, Richard J.,Caddick, Stephen
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p. 7301 - 7317
(2013/10/22)
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- Aerobic oxidation of primary aliphatic alcohols over bismuth oxide supported platinum catalysts in water
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Catalytic oxidation of non-activated aliphatic alcohols with molecular oxygen is rather challenging, especially in an aqueous medium in the absence of an additional base. Bismuth is usually used as a promoter of platinum-based catalysts. In this work, bismuth oxide was explored as a support, and Pt 0 nanoparticles supported on bismuth oxide (Pt/Bi2O 3) exhibited high activity for aerobic oxidation of n-butanol using water as a solvent in the absence of an additional base under optimized conditions. Besides n-butanol, liquid primary aliphatic alcohols with low solubility in water could also be smoothly oxidized into the corresponding carbonyl compounds with molecular oxygen. Pt/Bi2O3 reduced by H2 at about 200 °C showed the highest activity for aerobic oxidation of n-butanol. At this temperature, platinum oxide was reduced to Pt0 and bismuth oxide could be reduced partially which might change the surface property of bismuth oxide.
- Lu, Tianliang,Du, Zhongtian,Liu, Junxia,Ma, Hong,Xu, Jie
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p. 2215 - 2221
(2013/09/24)
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- Insights into support wettability in tuning catalytic performance in the oxidation of aliphatic alcohols to acids
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A superhydrophobic catalyst was prepared by immobilizing Pt nanoparticles on superhydrophobic organic-inorganic hybrid silicas, which showed high activity and selectivity in the oxidation of aliphatic alcohols to carboxylic acids.
- Wang, Min,Wang, Feng,Ma, Jiping,Chen, Chen,Shi, Song,Xu, Jie
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supporting information
p. 6623 - 6625
(2013/07/26)
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- Sinapyl alcohol derivatives from the lipo-soluble part of Dichrocephala benthamii C. B. Clarke
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Four new sinapyl alcohol derivatives dichrocephols A-D (compounds 1-4) were isolated from the lipo-soluble part of the whole herb of Dichrocephala benthamii C. B. Clarke, together with the known compound syringenin isovalerate (5). Their structures were elucidated on the basis of spectroscopic analysis. Their absolute configurations were established by the method of alkaline hydrohysis. Compounds 1-3 showed moderate cytotoxity against HeLa cells, with IC50 values of 14.8 μM, 51.6 μM and 81.6 μM, respectively. This is the first time that sinapyl alcohol derivatives were isolated from the genus Dichrocephala.
- Tian, Xinhui,Ding, Gang,Peng, Chaozhong,Hu, Yanbao,Li, Li,Chen, Hong,Zou, Zhongmei
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p. 1720 - 1727
(2013/04/24)
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- Novel coenzyme B12-dependent interconversion of isovaleryl-CoA and pivalyl-CoA
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5′-Deoxyadenosylcobalamin (AdoCbl)-dependent isomerases catalyze carbon skeleton rearrangements using radical chemistry. We have recently characterized a fusion protein that comprises the two subunits of the AdoCbl-dependent isobutyryl- CoA mutase flanking a G-protein chaperone and named it isobutyryl-CoA mutase fused (IcmF). IcmF catalyzes the interconversion of isobutyryl-CoA and n-butyryl-CoA, whereas GTPase activity is associated with its G-protein domain. In this study, we report a novel activity associated with IcmF, i.e. the interconversion of isovaleryl-CoA and pivalyl-CoA. Kinetic characterization of IcmF yielded the following values: a Km for isovaleryl-CoA of 62 ± 8 μM and Vmax of 0.021 ± 0.004 μmol min-1 mg-1 at 37 ° C. Biochemical experiments show that an IcmF in which the base specificity loop motif NKXD is modified to NKXE catalyzes the hydrolysis of both GTP and ATP. IcmF is susceptible to rapid inactivation during turnover, and GTP conferred modest protection during utilization of isovaleryl-CoA as substrate. Interestingly, there was no protection from inactivation when either isobutyryl-CoA or n-butyryl-CoA was used as substrate. Detailed kinetic analysis indicated that inactivation is associated with loss of the 5′-deoxyadenosine moiety from the active site, precluding reformation of AdoCbl at the end of the turnover cycle. Under aerobic conditions, oxidation of the cob(II)alamin radical in the inactive enzyme results in accumulation of aquacobalamin. Because pivalic acid found in sludge can be used as a carbon source by some bacteria and isovaleryl- CoA is an intermediate in leucine catabolism, our discovery of a new isomerase activity associated with IcmF expands its metabolic potential.
- Cracan, Valentin,Banerjee, Ruma
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experimental part
p. 3723 - 3732
(2012/06/15)
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- PROCESS AND DEVICE FOR THE OXIDATION OF ORGANIC COMPOUNDS
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The invention relates to a process for the oxidation of organic compounds by means of oxygen, in which, in a first step, the organic compound and at least part of the oxygen required for the oxidation are introduced into a first reaction zone which is operated isothermally and with backmixing and, in a second step, the reaction mixture from the first reaction zone is introduced into a second reaction zone which is operated adiabatically. The invention further relates to a reactor for carrying out the process, which comprises at least one isothermal reaction zone (3, 5) and an adiabatic reaction zone (7) which are arranged in a reactor shell (8), with each isothermal reaction zone (3, 5) being configured in the form of a jet loop reactor and the adiabatic reaction zone (7) being configured as a bubble column.
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Page/Page column 6
(2011/04/25)
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- Green syntheses of biobased solvents
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The design of bioproducts implies the use of renewable carbon but also the conversion of this carbon through clean processes. This step is often a limiting one if we consider the whole life cycle "from the raw materials to the fate of the products". We proposed, in this work, to adapt conventional methods to the conversion of a natural raw material, the fusel oil, a co-product generated by ethanol industry to prepare acetates, carbonates and isovalerates. Selected conditions are compared to conventional routes to quantify their ecoefficiency and to check their potential development for the preparation of new biosolvents. In another step, we have calculated the volatile organic compound amount emitted during the production of a new cosmetic formulation using the fusel oil derivatives. This complete but simple example shows how to identify a real competitive alternative to the usual production chains.
- Bandres, Matthieu,De Caro, Pascale,Thiebaud-Roux, Sophie,Borredon, Marie-Elisabeth
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experimental part
p. 636 - 646
(2012/04/10)
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- A kinetic approach to the oxidation of some perfumery alcohols by N-Bromosuccinimide in alkaline medium
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The aliphatic alcohols, 2-propanol, 2-butanol and 3-methyl-1-butanol are extensively used as diluents in the manufacture of perfumes. Secondary alcohols, borneol, isoborneol and menthol are used in the preparation of fragrances, flavours and cosmetics. The pseudo first order kinetics of the oxidation of these alcohols has been studied using N-bromosuccinimide in alkaline medium as the oxidant. The progress of the reaction was monitored by iodometric titration of the unreacted oxidant at regular time intervals. The rate constants (k) of the oxidation reaction were determined from the straight lines plots of log (a-x) versus time. The effects of (i) alcohol concentration (ii) oxidant concentration (iii) ionic strength (iv) temperature in the range 303-318 K on the oxidation rate has been studied in detail. It was observed that the reaction rate increases with [Alc] but decreases with oxidant concentration. The oxidation rate increases with ionic strength. From the effect of temperature on the reaction rate, the energy of activation and other thermodynamic activation parameters, ΔH*, ΔG* and ΔS* have been evaluated. Suitable reaction mechanism and rate laws have suggested for the oxidation process. The oxidation rates follow the sequence: (1) for aliphatic alcohols, 2-propanol > 2-butanol > 3-methyl-1-butanol, which has been explained on the basis of chain length. (2) for secondary alcohols borneol > isoborneol > menthol, which has been explained on the basis of structures, steric factors and isomeric characteristics of the alcohols under study.
- Prabhu,Parbat,Tandel
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experimental part
p. 5495 - 5498
(2012/07/14)
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- Polyvinylpyrrolidone-supported hydroperoxide for selective oxidation of aldehydes to carboxylic acids and sulfides to sulfoxides
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The facile immobilization of hydroperoxide on the cross-linked poly(vinylpyrrolidone) is described by treatment of a poly(vinylpyrrolidone)- Vilsmeier adduct with (35%) hydrogen peroxide. The in situ-generated poly(vinyl pyrrolidone)-supported hydroperoxide reagent showed very good performance in chemoselective oxidation of aldehydes to carboxylic acids as well as sulfides to sulfoxides. Supplemental materials are available for this article. Go to the publishers online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. Taylor & Francis Group, LLC.
- Lakouraj, Moslem Mansour,Aghajani, Bahareh,Mokhtary, Masoud
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experimental part
p. 2393 - 2401
(2011/03/17)
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- Dioxygen mediated hydroacylation of vinyl sulfonates and sulfones on water
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Herein we report a mild, facile method for the preparation of 1,4-keto-sulfonates and sulfones on water. Further synthetic manipulations can result in products that are not readily accessed by hydroacylation of electron rich alkenes.
- Chudasama, Vijay,Fitzmaurice, Richard J.,Ahern, Jenna M.,Caddick, Stephen
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scheme or table
p. 133 - 135
(2010/04/01)
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- Highly efficient solvent-free catalytic hydrogenation of solid alkenes and nitro-aromatics using Pd nanoparticles entrapped in aluminum oxy-hydroxide
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Solid alkenes and aromatic nitro compounds are readily hydrogenated to the corresponding alkanes without further reduction of other functional group and amino compounds in nearly quantitative yields in the presence of Pd nanoparticles entrapped in aluminum oxy-hydroxide under the solvent-free condition.
- Chang, Fei,Kim, Hakwon,Lee, Byeongno,Park, Sungho,Park, Jaiwook
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experimental part
p. 4250 - 4252
(2010/09/07)
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- Efficient CuCl-catalyzed selective and direct oxidation of β- And γ-substituted aliphatic primary alcohols to carboxylic acids
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A new procedure for the selective and direct oxidation of aliphatic primary alcohols having substitution at - and -positions to corresponding carboxylic acids was developed using a catalytic amount of ligand and additive-free CuCl with anhydrous tBuOOH in acetonitrile solvent under very mild reaction conditions. This procedure is very simple and mild and works efficiently without any additives at room temperature.
- Mannam, Sreedevi,Sekar, Govindasamy
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experimental part
p. 2822 - 2829
(2010/10/20)
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- 2-(Trimethylsilyl)-1,3-dithiane 1-oxide as a convenient reagent for the transformation of aldehydes and ketones into homologous carboxylic acids
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Aldehydes and ketones were converted into the corresponding homologous carboxylic acids in two steps by treatment with 2-(trimethylsilyl)-1,3-dithiane 1-oxide. A modified Peterson olefination of the carbonyl compounds gave ketene thioacetal sulfoxides that were readily cleaved in acidic acetonitrile to give the required carboxylic acids. Georg Thieme Verlag Stuttgart New York.
- Krohn, Karsten,Cludius-Brandt, Stephan
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experimental part
p. 2616 - 2620
(2010/09/10)
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- Hypervalent λ3-bromane strategy for Baeyer-Villiger oxidation: Selective transformation of primary aliphatic and aromatic aldehydes to formates, which is missing in the classical Baeyer-Villiger oxidation
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A conceptually distinct, modern strategy for Baeyer-Villiger oxidation (BVO) was developed. Our novel method involves initial hydration of water to carbonyl compounds, followed by ligand exchange of hypervalent aryl-λ3-bromane on bromane(III) with the resulting hydrate, yielding a new type of activated Criegee intermediate. The intermediate undergoes BV rearrangement and produces an ester via facile reductive elimination of an aryl-λ3-bromanyl group, because of the hypernucleofugality. The novel strategy makes it possible to induce selectively the BV rearrangement of straight chain primary aliphatic as well as aromatic aldehydes, which is missing in the classical BVO: for instance, octanal and benzaldehyde afforded rearranged formate esters with high selectivity (>95%) under our conditions, while the attempted classical BVO produced only carboxylic acids. This firmly establishes the powerful nature of new methodology for BVO.
- Ochiai, Masahito,Yoshimura, Akira,Miyamoto, Kazunori,Hayashi, Satoko,Nakanishi, Waro
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supporting information; experimental part
p. 9236 - 9239
(2010/11/02)
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- Rapid chemoselective deprotection of benzyl esters by nickel boride
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Benzyl esters of a variety of acids can be chemoselectively cleaved on treatment with nickel boride in methanol at ambient temperature to give the parent carboxylic acids in high yields. Other protecting functionalities such as methyl, ethyl, tert-butyl, and trityl esters as well as benzyl ethers, tert-butyl ethers, and Nbenzylamides are unaffected under these conditions. Georg Thieme Verlag Stuttgart.
- Khurana, Jitender M.,Arora, Reema
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experimental part
p. 1127 - 1130
(2009/12/03)
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- Formal highly enantioselective organocatalytic addition of alkyl anions to α,β-unsaturated aldehydes: Application to the synthesis of isotope-enantiomers
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A practical and powerful methodology that constitutes an organocatalytic alternative for organometallic 1,4-additions was developed. In a vial, bis(phenylsulfonyl)methane and catalyst V were added to toluene. Next, unsaturated aldehyde 1a was added and th
- Alba, Andrea-Nekane,Companyo, Xavier,Moyano, Albert,Rios, Ramon
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scheme or table
p. 11095 - 11099
(2010/04/26)
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- Electrocatalytic carboxylation of aliphatic halides at silver cathode in acetonitrile
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A simple and efficient electrocarboxylation reaction of aliphatic halides has been developed using silver as cathode, magnesium as anode and CH3CN saturated CO2 as solvent in an undivided cell. The influence of some key factors (such as the nature of electrode materials, supporting electrolytes and temperature) on this reaction was investigated. Under the optimized condition, the corresponding carboxylic acids were obtained in moderate to good yields (22-89%). The electrochemical behaviour was studied at different electrodes (Ag, Cu, Ni and Ti) by cyclic voltammetry, which showed significant electrocatalytic effect of the silver electrode towards the reductive carboxylation of aliphatic halides.
- Niu, Dong-Fang,Xiao, Li-Ping,Zhang, Ai-Jian,Zhang, Gui-Rong,Tan, Qi-Yun,Lu, Jia-Xing
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p. 10517 - 10520
(2008/12/23)
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- Perhydrolase
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The present invention provides methods and compositions comprising at least one perhydrolase enzyme for cleaning and other applications. In some particularly preferred embodiments, the present invention provides methods and compositions for generation of peracids. The present invention finds particular use in applications involving cleaning, bleaching and disinfecting.
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Page/Page column 51-53
(2008/12/06)
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- Clean and highly selective oxidation of alcohols by the Phl(OAc) 2/Mn(TPP)CN/lm catalytic system
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An efficient method for the oxidation of alcohols is presented. Using catalytic amounts of manganese porphyrin [Mn(TPP)CN] in combination with (diacetoxyiodo)benzene (Phl(OAc)2) allows the conversion of benzylic and primary aliphatic and aromatic alcohols into the corresponding aldehydes, and secondary alcohols to ketones as the sole products. This method provides a cost-effective and environmentally friendly oxidation procedure due to the utilisation of less toxic Phl(OAc)2 and biologically relevant manganese porphyrins. The amounts of the products (%) and the selectivities are very dependent upon the nature of the metalloporphyrin catalysts and also upon the electronic and steric properties of the starting alcohols.
- Karimipour, Gholam Reza,Shadegan, Hamid Asadpour,Ahmadpour, Roxana
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p. 252 - 256
(2008/02/08)
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- Catalytic process for preparing aliphatic straight-chain and beta-alkyl-branched carboxylic acids
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A catalytic process for preparing aliphatic straight-chain and β-alkyl-branched carboxylic acids of 5 to 13 carbon atoms by catalytic oxidation of the corresponding aldehydes by means of oxygen or oxygen-containing gas mixtures in the liquid phase in the presence of a catalyst system contains alkali metal carboxylates or alkaline earth metal carboxylates or a mixture thereof in an amount, calculated as alkali metal or alkaline earth metal, of 0.5 mmol to 15 mmol per mol of aldehyde used and also metals of groups 4 to 12 of the Periodic Table of the Elements, cerium or lanthanum in amounts of not more than 5 ppm, based on the aldehyde used, or compounds of such metals, with the catalyst system being the reaction product from an aldehyde oxidation reaction.
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Page/Page column 7-8; 10
(2008/06/13)
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- Structure activity studies with xenobiotic substrates using carboxylesterases isolated from Arabidopsis thaliana
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Carboxylesterases (CXEs) catalyse the hydrolysis of xenobiotics and natural products radically altering their biological activities. Whereas the substrate selectivity of animal CXEs, such as porcine liver esterase (PLE) have been well studied, the respective enzymes in plants have yet to be defined and their activities determined. Using Arabidopsis thaliana (At) as a source, five representative members of the α/β hydrolase AtCXE family of proteins have been cloned, expressed and the purified recombinant proteins assayed for esterase activity with xenobiotic substrates. Two members, AtCXE5 and AtCXE18 were found to be active carboxylesterases, though AtCXE5 proved to be highly unstable as a soluble protein. AtCXE18 and the previously characterised S-formylglutathione hydrolase from Arabidopsis (AtSFGH) were assayed against a series of esters based on methylumbelliferone in which the acyl moiety was varied with respect to size and conformation. The same series was used to assay crude esterase preparation from Arabidopsis plants and the results compared with those obtained with the commonly used PLE. With straight chain esters, AtCXE18 behaved like PLE, but the Arabidopsis hydrolases proved less tolerant of branched chain acyl components than the mammalian enzyme. While none of the enzyme preparations accurately reflected all the activities determined with crude Arabidopsis protein extracts, the plant enzymes proved more useful than PLE in predicting the hydrolysis of the more sterically constrained esters.
- Cummins, Ian,Landrum, Marie,Steel, Patrick G.,Edwards, Robert
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p. 811 - 818
(2008/03/13)
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- 2-Hydroxy-1,2,2-triphenylethanone as an efficient photolabile protecting group for carboxylic acids
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The synthesis is reported of 2-hydroxy-1,2,2-triphenylethanone esters of carboxylic acids by the reaction between 2-chloro-1,2,2-triphenylethanone and a carboxylic acid in the presence of silver carbonate and silver tetrafluoroborate. Photolysis of the esters occurs rapidly on irradiation with a medium-pressure mercury lamp through quartz or Pyrex to return the carboxylic acid. The side product of the photolysis is benzo[b]phenanthro[9,10-d]furan, formed through a tandem process involving initial generation of 2,3-diphenylbenzofuran, photochemical cyclisation and re-aromatisation by aerial oxidation.
- Ashraf, M. Arfan,Russell, Alexander G.,Wharton, Christopher W.,Snaith, John S.
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p. 586 - 593
(2007/10/03)
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- Mild conversion of β-diketones and β-ketoesters to carboxylic acids
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A mild protocol for the conversion of β-ketoesters and β-diketones to carboxylic acids with use of CAN in CH3CN is described. The method is compatible with a number of functional groups, and can generate carboxylic acids under neutral conditions at room temperature. The reaction is fast and general, providing an alternative method to the commonly used malonic ester acid preparation. Initial mechanistic studies show that initial oxidation of the enol form of the β-dicarbonyl initiates the reaction. The presence of nitrate as an oxidant ligand or as an additive is critical for success of the reaction.
- Zhang, Yang,Jiao, Jingliang,Flowers II, Robert A.
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p. 4516 - 4520
(2007/10/03)
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- Steric effects in the uncatalyzed and DMAP-catalyzed acylation of alcohols - Quantifying the window of opportunity in kinetic resolution experiments
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The kinetics of the reaction of several alcohols (benzyl alcohol, ethanol, 1-phenylethanol, cyclohexanol, and 1-methyl-1-phenylethanol) with a selection of anhydrides (acetic anyhydride, propionic anhydride, isobutyric anhydride, isovaleric anhydride, and pivalic anhydride) as catalyzed by 4-(N,N-dimethylamino)pyridine (DMAP)/triethyl amine have been studied in CH 2Cl2 at 20°C. In all cases the reaction kinetics can be described by rate laws containing a DMAP-catalyzed term and an uncatalyzed (back-ground) term. The rate constants for the background reaction respond sensi tively to changes in the steric demand of the alcohol and the anhydride substrates, making the reaction of cyclohexanol with acetic anhydride 526 times faster than the reaction with pivalic anhydride. Steric effects are even larger for the catalyzed reaction and the reactivity difference between acetic and pivalic anhydride exceeds a factor of 8000 for the reaction of cyclohexa nol. There is, however, no linear correlation between the steric effects on the catalyzed and the uncatalyzed part. As a consequence there are substrate combinations with dominating catalytic terms (such as the reaction of benzyl alcohol with isobutyric anhydride), while other substrate combinations (such as the reaction of cyclohexanol with pivalic anhydride) are characterized through a dominating background process. The implications of these findings for the kinetic resolution of alcohols are discussed.
- Fischer, Christian B.,Xu, Shangjie,Zipse, Hendrik
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p. 5779 - 5784
(2008/03/14)
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- Process for the preparation of aliphatic linear and ?-alkyl-branched carboxylic acids
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Preparation of aliphatic straight chain or beta -alkyl branched 5-13C alkyl carboxylic acid (I) comprises oxidizing an aldehyde with oxygen or oxygen-containing gas mixtures at 20-100[deg]C in the presence of an alkali and/or alkaline earth metal carboxylate, where the quantity of alkali or alkaline earth metal is calculated as 1-10 mmol/mol of used aldehyde, and group 5-11 metal (compound). Preparation of aliphatic straight chain or beta -alkyl branched 5-13C alkyl carboxylic acid (I) comprises oxidation of an aldehyde with oxygen or oxygen-containing gas mixtures at 20-100[deg]C in the presence of an alkali and/or alkaline earth metal carboxylate, where the quantity of alkali or alkaline earth metal is 1-10 mmol/mol of aldehyde and in the present of 0.1-5 ppm of a metal of the groups 5-11 of the periodic table of the elements or the corresponding quantity of a compound such as metal or its mixtures and/or metallic components, based on used aldehyde.
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Page/Page column 8-9; 11
(2008/06/13)
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- An efficient method for the synthesis of aliphatic acids using microwaves
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Aliphatic acids are prepared by reaction of nitriles with phtalic acid by irradiation under microwaves in a domestic oven.
- Brǎtulescu, George
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p. 161 - 163
(2007/10/03)
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- A series of crystal structures of a meta-cleavage product hydrolase from Pseudomonas fluorescens IP01 (CumD) complexed with various cleavage products
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Meta-cleavage product hydrolase (MCP-hydrolase) is one of the key enzymes in the microbial degradation of aromatic compounds. MCP-hydrolase produces 2-hydroxypenta-2,4-dienoate and various organic acids, according to the C6 substituent of the substrate. Comprehensive analysis of the substrate specificity of the MCP-hydrolase from Pseudomonas fluorescens IP01 (CumD) was carried out by determining the kinetic parameters for nine substrates and crystal structures complexed with eight cleavage products. CumD preferred substrates with long non-branched C6 substituents, but did not effectively hydrolyze a substrate with a phenyl group. Superimposition of the complex structures indicated that benzoate was bound in a significantly different direction than other aliphatic cleavage products. The directions of the bound organic acids appeared to be related with the kcat values of the corresponding substrates. The Ile139 and Trp143 residues on helix α4 appeared to cause steric hindrance with the aromatic ring of the substrate, which hampers base-catalyzed attack by water.
- Fushinobu, Shinya,Jun, So-Young,Hidaka, Masafumi,Nojiri, Hideaki,Yamane, Hisakazu,Shoun, Hirofumi,Omori, Toshio,Wakagi, Takayoshi
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p. 491 - 498
(2008/02/01)
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