- Oxidation of cyclohexanone and/or cyclohexanol catalyzed by Dawson-type polyoxometalates using hydrogen peroxide
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The oxidation of cyclohexanone, cyclohexanol or cyclohexanone/cyclohexanol mixture using as catalyst, Dawson-type polyoxometalates (POMs) of formula, α- and β-K6P2W18O62, α-K6P2Mo6W12O62 and α1-K7P2Mo5VW12O62 and hydrogen peroxide, carried out at 90 °C with a reaction time of 20 h, led to a high number of mono- and di-acids which were identified by GC-MS. Levulinic, 6-hydroxyhexanoic, adipic, glutaric and succinic acids, major products were evaluated by HPLC. Regardless of the substrate nature, all POMs exhibited high catalytic activity with 94–99% of conversion, whereas the formation of the different products is sensitively related to both the composition and symmetry of the POMs and the substrate nature. The main products are adipic acid in the presence of α-K6P2Mo6W12O62 and α1-K7P2Mo5VW12O62, levulinic acid in the presence of α1-K7P2Mo5VW12O62 and β-K6P2W18O62 and 6-hydroxyhexanoic acid in the presence of α- and β-K6P2W18O62. Graphical abstract: High catalytic activity was observed with?α- and?β-K6P2W18O62, α-K6P2Mo6W12O62 and α1-K7P2Mo5VW12O62 Dawson-type for the oxidation of cyclohexanone, cyclohexanol or cyclohexanone/cyclohexanol mixture, in the hydrogen peroxide presence, to several oxygenated products. Adipic, levulinic and 6-hydroxyhexanoic acids are the main products. The peroxo- species formed in situ could be the active sites.[Figure not available: see fulltext.]
- Dermeche, Leila,Idrissou, Yasmina,Mazari, Tassadit,Moudjahed, Mohammed,Rabia, Cherifa
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- Silica-Mediated Monohydrolysis of Dicarboxylic Esters
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A new method for the monohydrolysis of dicarboxylic esters is presented, involving as key step a silanolysis at elevated temperatures at the silica gel surface. In the second step, the surface bound silyl esters are cleaved off under mild conditions, giving a straightforward and fast access to half esters. Based on recovered starting material generally yields well above 70 % are achieved, both, with stiff aromatic as well as flexible aliphatic substrates, as long as the ester groups involved are remote enough from each other. Otherwise competing reactions are becoming determinative, anhydride formation in the case of phthalates and decarbonylative fragmentation in the case of malonates. The new method was also successfully tested on a multigram scale with a minimalistic apparatus setup.
- Dyker, Gerald
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supporting information
p. 6773 - 6776
(2021/12/31)
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- An adipic acid monoethyl synthetic method (by machine translation)
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An adipic acid monoethyl synthetic method, steps: firstly the adipic acid, acid, ethanol and water in the organic solvent heating and thermal insulation, and then removing the acid water level after the end of the thermal insulation layer, acid aqueous layer is re-used for the next round of the reaction, the organic layer obtained; the obtained organic layer concentrated, get the adipic acid monoethanol at the beginning of ester concentrate; will be adipic acid monoethanol at the beginning of ester concentrate extracted by the extractant continuous flow extraction purification, then the concentrated adipic acid monoethyl. The reaction mechanism is simple, short reaction time, adipic acid monoethyl of mol yield can be up to 97 - 98%, purity can be up to 99% or more; the consumption of acid and alkali is significantly reduced; the separate acid water layer can be repeatedly applied to the next round of reaction; simple process flow, simple operation, reducing the energy consumption, the labor intensity; reflect the green production; extraction process is simple, rapid and effective, and the extractant used after processing, saving the operation cost, easy industrialization enlarges the production and continuous operation. (by machine translation)
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Paragraph 0027; 0028; 0029; 0030; 0031; 0031; 0032-0082
(2017/09/01)
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- Carboxylation of Aromatic and Aliphatic Bromides and Triflates with CO2 by Dual Visible-Light–Nickel Catalysis
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We report the efficient carboxylation of bromides and triflates with K2CO3 as the source of CO2 in the presence of an organic photocatalyst in combination with a nickel complex under visible light irradiation at room temperature. The reaction is compatible with a variety of functional groups and has been successfully applied to the synthesis and derivatization of biologically active molecules. In particular, the carboxylation of unactivated cyclic alkyl bromides proceeded well with our protocol, thus extending the scope of this transformation. Spectroscopic and spectroelectrochemical investigations indicated the generation of a Ni0 species as a catalytic reactive intermediate.
- Meng, Qing-Yuan,Wang, Shun,K?nig, Burkhard
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supporting information
p. 13426 - 13430
(2017/10/07)
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- Selective monomethyl esterification of linear dicarboxylic acids with bifunctional alumina catalysts
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An environmentally friendly protocol for the selective protection of dicarboxylic acids is reported using methanol as a cheap esterifying agent and alumina as a heterogeneous catalyst; the selectivity of the process has been ascribed to a balanced acidity/basicity of the bifunctional alumina catalyst.
- Santacroce, Veronica,Bigi, Franca,Casnati, Alessandra,Maggi, Raimondo,Storaro, Loretta,Moretti, Elisa,Vaccaro, Luigi,Maestri, Giovanni
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supporting information
p. 5764 - 5768
(2016/11/06)
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- Mild Amide-Cleavage Reaction Mediated by Electrophilic Benzylation
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An extremely mild method for amide-cleavage by using the triazine-based benzylating reagent 4-(4,6-diphenoxy-1,3,5-triazin-2-yl)-4-benzylmorpholinium trifluoromethanesulfonate (DPT-BM), which spontaneously releases benzyl cation species when being dissolved at room temperature, has been developed. O-Benzylation of the amide with DPT-BM and the subsequent hydrolysis of the resulting intermediate benzyl imidate salt afford the corresponding amine and benzyl ester, which can be converted by hydrogenolysis into a carboxylic acid under neutral conditions. O-Benzylation proceeds depending on both steric and electronic factors around the amide group. Thus, some amides have been selectively cleaved over other amides. Furthermore, intramolecular chemoselective cleavage of an amide group in the presence of an ester group was achieved. Such selective hydrolytic reactions cannot be performed with Meerwein reagents as well as under acidic or basic hydrolytic conditions.
- Yamada, Kohei,Karuo, Yukiko,Tsukada, Yuichi,Kunishima, Munetaka
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supporting information
p. 14042 - 14047
(2016/09/21)
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- ALCOHOL-MEDIATED ESTERIFICATION OF CARBOXYLIC ACIDS WITH CARBONATES
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A process for making esters from organic acids by means of reacting a carboxylic acid with dialkylcarbonate in an alcohol-containing solvent without any extrinsic acid or base catalyst is described. A benefit of the preparation process is that it can make the separation and extraction of ester products simpler and more facile vis-a-vis conventional isolation techniques.
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Page/Page column 10
(2014/05/24)
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- PYRIDIN-2YL SULFANYL ACID ESTERS AND PROCESS FOR THE PREPARATION THEREOF
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The present invention relates to Pyridin-2-yl sulfanyl acid ester compounds having antiinflammatory properties. The present invention particularly relates to novel anti-inflammatory heterocyclic acid esters of Pyridin-2-yl sulfanyl having the structure of general formula 1 which have been screened for their antiinflammatory activity with respect to inhibition of adhesion of neutrophils, isolated from human peripheral blood, onto the surface of human umbilical vein endothelial cells (HU-VEC) as a result of inhibition of the cytokine-stimulated expression of cell adhesion molecule ICAM-1. The compound RS—Z, 3-(Pyridin-2-yl sulfanyl)-propionic acid pentyl ester (structure 1a, R1=H, R2=H, R3=CH2-COOC5H11) was found to be most effective for ICAM-1 and neutrophil adhesion inhibition and was found to effectively alleviate inflammation mediated by excessive leukocyte infiltration leading to inflammatory disorders or like conditions, such as acute lung injury and acute respiratory distress syndrome in mice.
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Paragraph 0155-0159; 0155-0159
(2013/06/04)
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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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- PYRIDIN- 2 - YL SULFANYL ACID ESTERS AND PROCESS FOR THE PREPARATION THEREOF
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The present invention relates to Pyridin-2-yl sulfanyl acid ester compounds having antiinflammatory properties. The present invention particularly relates to novel anti-inflammatory heterocyclic acid esters of Pyridin-2-yl sulfanyl having the structure of general formula 1 which have been screened for their antiinflammatory activity with respect to inhibition of adhesion of neutrophils, isolated from human peripheral blood, onto the surface of human umbilical vein endothelial cells (HUVEC) as a result of inhibition of the cytokine-stimulated expression of cell adhesion molecule ICAM-1. The compound RS-Z, 3-(Pyridin-2-yl sulfanyl)-propionic acid pentyl ester (structure la, R1 = H, R2 = H, R3 = CH2COOC5H11) was found to be most effective for ICAM-1 and neutrophil adhesion inhibition and was found to effectively alleviate inflammation mediated by excessive leukocyte infiltration leading to inflammatory disorders or like conditions, such as acute lung injury and acute respiratory distress syndrome in mice.
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Page/Page column 16-17
(2012/02/05)
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- Beyond Aresta's complex: Ni- and Pd-catalyzed organozinc coupling with CO2
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Organozinc reagents are widely used in organic synthesis due primarily to their high functional group compatibility. However, under mild conditions, these organometallic reagents do not react directly with CO2, the ideal C1 source for organic synthesis. Herein, we report that both Ni and Pd complexes can catalyze the addition of organozinc reagents to CO2 under mild conditions (1 atm CO2, 0 °C). This transformation represents an important extension of the Negishi cross-coupling and is believed to occur via a novel mechanism involving Aresta-s complex and/or its corresponding Pd analogue. Copyright
- Yeung, Charles S.,Dong, Vy M.
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supporting information; experimental part
p. 7826 - 7827
(2009/02/02)
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- Synthesis and anti-cancer activity of C-ring-functionalized prodigiosin analogues
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Prodigiosin is the parent member of the 4-methoxypyrrolyldipyrromethene family of natural products and is known for its anti-cancer activity. A new series of analogues was synthesized, incorporating pendent functional esters and β-carbonyl substituents on the C-ring. The β-carbonyl group allowed for the facile isolation of the prodigiosenes, and the pendent esters allow for further derivatization. The novel prodigiosenes generally retain the anti-cancer activity of prodigiosin in 60 human cell lines derived from nine cancer cell types, with neither the conjugated /3-carbonyl group, as either ketone or ester, nor the pendent ester significantly reducing the anti-cancer activity of the core skeleton.
- Regourd, Jasmine,Ali, Adeeb Al-Sheikh,Thompson, Alison
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p. 1528 - 1536
(2008/02/02)
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- Direct oxidative cleavage of α- and β-dicarbonyls and α-hydroxyketones to diesters with KHSO5
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Presented is a methodology to oxidatively cleave α-hydroxyketones and α- or β-diones using the environmentally benign reagent KHSO 5, prepared easily from Oxone, to diesters in one simple transformation. In addition, we undertook a mechanistic study to provide a plausible mechanistic interpretation. These reactions may prove to be valuable alternatives to other related metal-mediated processes.
- Yan, Jun,Travis, Benjamin R.,Borhan, Babak
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p. 9299 - 9302
(2007/10/03)
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- Facile and Clean Oxidation of Alcohols in Water Using Hypervalent Iodine (III) Reagents
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The facile and efficient oxidation of various alcohols such as benzylic alcohols, primary alcohols, secondary alcohols, and diols in water using the hypervalent iodine(III) reagent, iodosobenzene (PhI=O), with KBr is described. Electrospray ionization (ESI) mass spectrometric studies on the behavior of PhI=O-KBr in aqueous solution suggested that these reactions are induced by the formation of highly reactive iodine species [PhI(Br)nO-]. Further development to recyclable polymer-supported iodine(III) reagent extends the utility of this reaction to afford an environmentally benign method.
- Tohma, Hirofumi,Maegawa, Tomohiro,Takizawa, Shinobu,Kita, Yasuyuki
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p. 328 - 337
(2007/10/03)
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- Facile and clean oxidation of alcohols in water using hypervalent iodine(III) reagents
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An environmentally benign oxidation of alcohols in water using iodosobenzene (PhI=O) or a polymer-supported (diacetoxyiodo)benzene (PSDIB) with KBr has been achieved (see scheme). This method results in the catalytic activation of a variety of sluggishly reactive and/or sparsely soluble hypervalent iodine reagents in water under neutral conditions.
- Tohma, Hirofumi,Takizawa, Shinobu,Maegawa, Tomohiro,Kita, Yasuyuki
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p. 1306 - 1308
(2007/10/03)
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- Selective monoesterification of dicarboxylic acids catalysed by ion-exchange resins
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Symmetrical dicarboxylic acids with 4-14 carbon atoms gave selectively the corresponding monoesters in high yields in the transesterification catalysed by strongly acidic ion-exchange resins in ester-hydrocarbon mixtures. It was found that the rate of the esterification of the dicarboxylic acids is much higher than that of the monocarboxylic acids formed. This result can explain the high selectivity for the monoester formation and can also be explained by the existence of an aqueous layer on the surface of the resins. This method of selective esterification is quite simple and practical. The Royal Society of Chemistry 1999.
- Nishiguchi, Takeshi,Ishii, Yasuhiro,Fujisaki, Shizuo
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p. 3023 - 3027
(2007/10/03)
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- Iron (III) perchlorate: A reagent for trans-esterification
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Iron (III) perchlorate has successfully been used for the trans-esterification of ethyl acetate with alcohols and acids.
- Kumar, Baldev,Kumar, Harish,Parmar, Anupama
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p. 292 - 293
(2007/10/02)
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- HYDROLYSIS IN THE ABSENCE OF BULK WATER 1. CHEMOSELECTIVE HYDROLYSIS OF AMIDES USING TETRAHALOPHTALIC ANHYDRIDES
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The reaction of primary and secondary amides with tetrafluorophthalic or tetrachlorophtalic anhydride gives carboxylic acids in good yield.The reaction is chemoselective in that the amide functionality can be hydrolyzed in the presence of ester groups.
- Eaton, Jefferson T.,Rounds, William D.,Urbanowicz, John H.,Gribble, Gordon W.
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p. 6553 - 6556
(2007/10/02)
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- A CONVENIENT METHOD FOR THE DIRECT PREPARATION OF KETONES FROM 2-(6-(2-METHOXYETHYL)PYRIDYL) CARBOXYLATES AND ALKYL IODIDES BY USE OF ZINC DUST AND A CATALYTIC AMOUNT OF NICKEL DICHLORIDE
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Treatment of 2-(6-(2-methoxyethyl)pyridyl) carboxylates with alkyl iodides in the presence of zinc dust and a catalytic amount of NiCl2 in DMF at 50 deg C affords unsymmetrical ketones in good yields by a one-pot procedure.
- Onaka, Makoto,Matsuoka, Yoshio,Mukaiyama, Teruaki
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p. 531 - 534
(2007/10/02)
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- Crown ether catalysis of decarboxylation and decarbalkoxylation of β-keto acids and malonates: a synthetic application
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The effect of 18-crown-6 ether on the decarboxylation rates of the sodium and potassium salts of 3-camphor carboxylic acid 1 and of 1-carbomethoxy-1-carboxycyclohexane 2 was studied.For 2 the K-18C6 salt reacted ca. 104 times faster than the parent acid.This remarkable difference in reactivity was used in developing a one-pot, two-step procedure for decarbalkoxylation of malonic esters.This procedure was then applied to a range of malonates, β-keto esters, and an α-cyano ester.The effect of 15C5, other cations, and good nucleophiles was also studied.
- Hunter, Duncan H.,Patel, Vijay,Perry, Richard A.
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p. 2271 - 2277
(2007/10/02)
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- Pyrrole cephalosporin derivatives
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New pyrrole derivatives of cephalosporin compounds have been prepared which are useful as antibiotics.
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