- Oxidation of cyclohexanone and/or cyclohexanol catalyzed by Dawson-type polyoxometalates using hydrogen peroxide
-
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
-
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
-
supporting information
p. 6773 - 6776
(2021/12/31)
-
- Preparation method 6 -hydroxy caproic acid
-
The invention provides a preparation method of 6 -hydroxycaproic acid. The method comprises the following steps: 1) subjecting 1 and 6 - adipic acid to intramolecular dehydration to obtain adipic anhydride. 2) The adipic acid anhydride is reacted with fatty alcohol to obtain the adipic acid monoester. 3) The adipic acid monoester was subjected to a reduction reaction under hydrogen pressure to give 6 - hydroxycaproic acid. 1-hydroxycaproic acid is prepared by taking 6 - and 6 - adipic acid cheap and easily available as raw materials through intramolecular dehydration, ring opening esterification, hydrogenation reduction and the like.
- -
-
Paragraph 0056; 0071-0077; 0093; 0099-0101; 0107; 0113-0115
(2021/11/10)
-
- Discovery of 6-Oxo-4-phenyl-hexanoic acid derivatives as RORγt inverse agonists showing favorable ADME profile
-
The retinoic acid receptor-related orphan nuclear receptor gamma t (RORγt), which is a promising therapeutic target for immune diseases, is a major transcription factor of genes related to psoriasis pathogenesis, such as interleukin (IL)-17A, IL-22, and IL-23R. Inspired by the co-crystal structure of RORγt, a 6-oxo-4-phenyl-hexanoic acid derivative 6a was designed, synthesized, and identified as a ligand of RORγt. The structure–activity relationship (SAR) studies in 6a, which focus on the improvement of its membrane permeability profile by introducing chlorine atoms, led to finding 12a, which has a potent RORγt inhibitory activity and a favorable pharmacokinetic profile.
- Nakajima, Ryota,Oono, Hiroyuki,Kumazawa, Keiko,Ida, Tomohide,Hirata, Jun,White, Ryan D.,Min, Xiaoshan,Guzman-Perez, Angel,Wang, Zhulun,Symons, Antony,Singh, Sanjay K.,Mothe, Srinivasa Reddy,Belyakov, Sergei,Chakrabarti, Anjan,Shuto, Satoshi
-
supporting information
(2021/02/09)
-
- NOVEL ESTERIFICATION CATALYST AND USES THEREOF
-
Tin (II) glucarate is found to be effective alone and in combination with other tin compounds for catalyzing the reaction of carboxylic acids such as furan-2,5-dicarboxylic acid, terephthalic acid and adipic acid with alcohols such as the C1-C3 alcohols.
- -
-
Page/Page column 0026; 0028-0029
(2020/07/07)
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- NOVEL PROCESS FOR THE PREPARATION OF 1,3-THIAZOL-5-YLMETHYL [(2R,5R)-5- CARBAMOYL) AMINO] -4-(MORPHOLIN-4-YL)BUTANOYL]AMINO}-1,6-DIPHENYLHEXAN-2-YL]CARBAMATE
-
The present invention relates to novel processes for the preparation 1,3-Thiazol-5-ylmethyl[(2R,5R)-5-{[(2S)-2-[(methyl{[2-(propan-2-yl)-1,3-thiazol-4-yl]methyl} carbamoyl)amino]-4-(morpholin-4-yl)butanoyl]amino}-1,6-diphenylhexan-2-yl] carbamate having the following structural formula-1 and it's intermediates thereof.
- -
-
Paragraph 0151
(2018/02/28)
-
- ORGANOTIN CATALYSTS IN ESTERIFICATION PROCESSES OF FURAN-2,5-DICARBOXYLIC ACID (FDCA)
-
A method for preparing sugar-based mono and diesters is described. The process entails the esterification of 2,5-furan-dicarboxylic acid (FDCA) with an alcohol in the presence of low loadings of a homogeneous organotin (IV) catalyst.
- -
-
Paragraph 0062
(2018/06/06)
-
- Iron-Catalyzed Aerobic Oxidation of Aldehydes: Single Component Catalyst and Mechanistic Studies
-
An aerobic oxidation of aldehydes towards carboxylic acids in MeCN using 1 atm of pure oxygen or oxygen in air as the oxidant and a catalytic amount of single component catalyst, Fe(NO3)3·9H2O, has been developed. Carboxylic acids with different synthetically useful functional groups were obtained at room temperature. Two mechanistic pathways have been proposed based on isotopic labeling, NMR monitoring, and control experiments. The practicality of this reaction has been demonstrated by conducting several 50 mmol-scale reactions using pure oxygen or an air-flow of ~30 mL/min.
- Jiang, Xingguo,Zhai, Yizhan,Chen, Junyu,Han, Yulin,Yang, Zheng,Ma, Shengming
-
supporting information
p. 15 - 19
(2017/11/23)
-
- Method for preparing acid through oxidating alcohols or aldehydes by oxygen
-
The invention provides a method for preparing acid through oxidating alcohols or aldehydes by using oxygen or oxygen in air as an oxidant. The method comprises the steps: oxidating the alcohols or aldehydes to produce the acid at room temperature in an organic solvent in a manner of taking ferric nitrate (Fe(NO3)3.9H2O), 2,2,6,6-tetramethylpiperidyl nitrogen oxide (TEMPO) and an inorganic halide as catalysts and taking the oxygen or air as an oxidant, and oxidating diols to produce lactone; or, carrying out a reaction on the aldehydes, which serve as a raw material, under neutral conditions by taking ferric nitrate as a catalyst, and oxidating the aldehydes to produce the acid and peroxy acid. The method has the advantages that the method is environmentally friendly, the cost is low, the yield is high, the atomic economical efficiency is high, the compatibility of substrate functional groups is good, the reaction conditions are mild, a reaction scale can be enlarged, and the like, so that the method is suitable for being applied to industrial production.
- -
-
Paragraph 0051; 0052; 0053; 0054; 0064; 0065; 0066
(2017/09/29)
-
- Sulfonated porous organic polymer as a highly efficient catalyst for the synthesis of biodiesel at room temperature
-
A new functionalized porous organic polymer bearing sulfonic acid groups (PDVTA-SO3H) at the pore surface with high surface area (SBET = 406 m2 g-1) and Bronsted acidity is reported. The material has been synthesized via post-synthetic sulfonation of the porous co-polymer poly-divinylbenzene-co-triallylamine (PDVTA-1) using chlorosulfonic acid as sulfonating agent. A detailed characterization of the -SO3H functionalized porous polymeric material has been carried out using N2 sorption, FT-IR and UV-vis spectroscopy, HR-TEM, FE-SEM, thermogravimetric and elemental analyses. Temperature programmed desorption of NH3 (TPD-NH3 analysis) of PDVTA-SO3H revealed a very high surface acidity of 2.3 mmol g-1. Such high acidity of PDVTA-SO3H has been explored to investigate its catalytic efficiency towards eco-friendly production of biodiesel via esterification of long-chain free fatty acids (FFA) to the respective fatty acid monoalkyl esters (FAMEs) at room temperature using methanol as reactant as well as solvent. The sulfonated porous polymer is found to be a very active and reusable solid acid catalyst giving high yields (~92-98%) of various biodiesel compounds under very mild reaction conditions.
- Gomes, Ruth,Bhanja, Piyali,Bhaumik, Asim
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p. 110 - 116
(2015/11/11)
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- γ-Lactone Synthesis via Palladium(II)-Catalyzed Lactonization of Unactivated Methylene C(sp3)-H Bonds
-
A palladium(II)-catalyzed intramolecular lactonization of unactivated methylene C(sp3)-H bonds using PIP bidentate auxiliary is described. This method provides an efficient and concise pathway to synthesize functionalized γ-lactones.
- Liu, Bin,Shi, Bing-Feng
-
supporting information
p. 2396 - 2400
(2016/09/28)
-
- Selective monomethyl esterification of linear dicarboxylic acids with bifunctional alumina catalysts
-
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
-
supporting information
p. 5764 - 5768
(2016/11/06)
-
- Iron Catalysis for Room-Temperature Aerobic Oxidation of Alcohols to Carboxylic Acids
-
Oxidation from alcohols to carboxylic acids, a class of essential chemicals in daily life, academic laboratories, and industry, is a fundamental reaction, usually using at least a stoichiometric amount of an expensive and toxic oxidant. Here, an efficient and practical sustainable oxidation technology of alcohols to carboxylic acids using pure O2 or even O2 in air as the oxidant has been developed: utilizing a catalytic amount each of Fe(NO3)3·9H2O/TEMPO/MCl, a series of carboxylic acids were obtained from alcohols (also aldehydes) in high yields at room temperature. A 55 g-scale reaction was demonstrated using air. As a synthetic application, the first total synthesis of a naturally occurring allene, i.e., phlomic acid, was accomplished.
- Jiang, Xingguo,Zhang, Jiasheng,Ma, Shengming
-
supporting information
p. 8344 - 8347
(2016/07/26)
-
- Sustainable production of dimethyl adipate by non-heme iron(iii) catalysed oxidative cleavage of catechol
-
Adipic acid and its esters are important bulk chemicals whose principal use is in the production of the nylon-6,6 polymer. There is considerable interest in finding novel green routes from sustainable feedstocks towards these important intermediates. Herein, we describe the catalytic oxidative cleavage of catechol to muconic acids using a catalyst prepared in situ from iron(iii) nitrate, tris(2-pyridylmethyl)amine and ammonium acetate. An investigation of catalyst loading, temperature and oxygen pressure, allowed a turnover frequency of 120 h-1 to be obtained. The subsequent hydrogenation and transesterification of the obtained muconic acid products were shown to proceed well over commercially available supported catalysts. After vacuum distillation, dimethyl adipate could be isolated in 62% yield from catechol, thus demonstrating a green and sustainable route to this important bulk chemical.
- Jastrzebski, Robin,Van Den Berg, Emily J.,Weckhuysen, Bert M.,Bruijnincx, Pieter C. A.
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p. 2103 - 2109
(2015/04/14)
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- ALCOHOL-MEDIATED ESTERIFICATION OF CARBOXYLIC ACIDS WITH CARBONATES
-
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 12
(2014/05/24)
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- PROCESS FOR THE PREPARATION OF ADIPIC ACID
-
The invention relates to a process for the preparation of adipic acid from adipic acid alkyl ester comprising: - subjecting an adipic acid alkyl ester to a hydrolysis reaction in the presence of water, at conditions of temperature and time suitable to form a hydrolysate comprising adipic acid; and - optionally recovering adipic acid from said hydrolysate, characterized in that the hydrolysis reaction is carried out in the initial presence of adipic acid, and further to adipic acid obtained by the process. The invention also relates to the use of adipic acid as an acid catalyst in the hydrolysis of adipic acid alkyl ester. The process may advantageously be carried out in the absence of a mineral acid or a heterogeneous catalyst. The adipic acid produces with the process may be low in metals and/or sulphates.
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Page/Page column 5; 6
(2014/07/08)
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- Synthesis of nitrogen-containing derivatives of (18α,19β)-19-Hydroxy-2,3-secooleanane-2,3,28-trioic Acid 28,19-Lactone
-
The object of this study is the interaction of the cyclic anhydride 2 of (18α,19β)-19-hydroxy-2,3-secooleanane-2,3,28-trioic acid 28,19-lactone (1) with primary and secondary amines. It was shown that the products of steric control (the corresponding 2-amino-2-oxo-3-oic acids=2-amides) were formed solely upon the opening of the anhydride cycle by secondary amines (Scheme 2), whereas the interaction with primary amines yielded a mixture of isomeric amides (Scheme 10). In the latter case, the solvent provided a noticeable effect on the reaction selectivity, which was demonstrated in the case of 4-methoxybenzylamine. The interaction between the resulting 3-amides and oxalyl chloride yielded the corresponding cyclic imides, whereas under these conditions, 2-amides formed spiropyrrolidinetriones (Scheme 4). Copyright
- Shernyukov, Andrey V.,Mainagashev, Ilya Ya.,Korchagina, Dina V.,Genaev, Alexander M.,Komarova, Nina I.,Salakhutdinov, Nariman F.,Tolstikov, Genrikh A.
-
p. 1757 - 1781
(2013/10/21)
-
- Insights into soluble guanylyl cyclase activation derived from improved heme-mimetics
-
Recently, the structure of BAY 58-2667 bound to the Nostoc sp. H-NOX domain was published. On the basis of this structural information, we designed BAY 58-2667 derivatives and tested their effects on soluble guanylyl cyclase (sGC) activity. Derivative 20 activated sGC 4.8-fold more than BAY 58-2667. Co-crystallization of 20 with the Ns H-NOX domain revealed that the increased conformational distortion at the C-terminal region of αF helix containing 110-114 residues contributes to the higher activation triggered by 20.
- Von Wantoch Rekowski, Margarete,Kumar, Vijay,Zhou, Zongmin,Moschner, Johann,Marazioti, Antonia,Bantzi, Marina,Spyroulias, Georgios A.,Van Den Akker, Focco,Giannis, Athanassios,Papapetropoulos, Andreas
-
p. 8948 - 8952
(2013/12/04)
-
- Design, synthesis and preliminary bioactivity studies of 1,3,4-thiadiazole hydroxamic acid derivatives as novel histone deacetylase inhibitors
-
Histone deacetylase (HDAC) inhibitors have emerged as a new class of anticancer agents, targeting the biological processes including cell cycle, apoptosis and differentiation. In the present study, a series of 1,3,4-thiadiazole based hydroxamic acids were developed as potent HDAC inhibitors. Some of them showed good inhibitory activity in HDAC enzyme assay and potent growth inhibition in some tumor cell lines. Among them, compound 6i (IC50 = 0.089 μM), exhibited better inhibitory effect compared with SAHA (IC50 = 0.15 μM).
- Guan, Peng,Sun, Feng'E,Hou, Xuben,Wang, Feng,Yi, Fan,Xu, Wenfang,Fang, Hao
-
experimental part
p. 3865 - 3872
(2012/08/27)
-
- A Ru-Sn-Co/AlO(OH) as a highly efficient catalyst for hydrogenation of dimethyl adipate to 1,6-hexanodiol in aqueous phase
-
A Ru-Sn-Co/AlO(OH) catalyst was prepared by co-impregnation, calcination, and hydrothermal reduction. The catalyst was well characterized by BET, XRD, SEM-EDX, XPS, H2-TPR, and M?ssbauer spectroscopy, and then it was applied in the hydrogenation of dimethyl adipate to 1,6-hexanodiol in aqueous phase. It was found that the addition of cobalt could stabilize Sn(IV) and the cooperation between tin and cobalt could promote the reduction of ruthenium oxide. The γ-Al2O3 in the catalyst Ru-Sn-Co/γ-Al2O3 was transformed to AlO(OH) by the hydrothermal reduction. It was suggested that the stabilized Sn(IV) and the interaction between the hydroxyl group on the surface of AlO(OH) and the solvent water played a key role to improve the conversion of dimethyl adipate and the selectivity to 1,6-hexanodiol. The conversion of dimethyl adipate and the selectivity to 1,6-hexanodiol were up to 98% and 95%, respectively, under 5 MPa of H2 and 493 K for 10 h.
- Jiang, Hong-Bin,Jiang, Hai-Jun,Su, Ke,Zhu, De-Ming,Zheng, Xue-Li,Fu, Hai-Yan,Chen, Hua,Li, Rui-Xiang
-
p. 164 - 170
(2013/03/13)
-
- Formal synthesis of (±)-roseophilin
-
A formal synthesis of (±)-roseophilin is described. Scandium(lll)-catalyzed Nazarov cyclization of 2,5-disubstituted N-tosylpyrrole 19 gives a 5,5'-fused ketopyrrole, and ansa-bridge formation via π-allyl palladium macrocyclization gives 21.
- Bitar, Abdallah Y.,Frontier, Alison J.
-
supporting information; experimental part
p. 49 - 52
(2009/07/04)
-
- SYNTHESIS OF HALF ESTERS
-
A method for hydrolyzing an ester is provided. In accordance with the method, a compound A is provided which has first and second ester moieties. The compound is reacted in a liquid medium with a base having the formula MaXb,such that the first ester moiety is converted to a carboxyl moiety and the second ester moiety remains, wherein the ratio [Xk-]:[A] in the liquid medium is no greater than 1.6, and wherein k > 0.
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-
Page/Page column 29-30
(2009/01/24)
-
- Clean and easy photochemistry
-
In this paper we try to convince you that the usual prejudices against photochemistry are not always well founded, supported by examples from the literature and from our own work. In fact, photochemistry can be a very powerful tool, for example in some elegant total syntheses which use key photochemical steps. Furthermore, the exploitation of chromatic orthogonality which allows wavelength-selective reactions, and recent strategies opening the possibility of enantioselective catalysis in photochemical reactions, expand the scope of this versatile synthetic tool. Finally, state-of-art LED-technology has allowed the development of small and easy-to-use photoreactors. Schweizerische Chemische Gesellschaft.
- Ciana, Claire-Lise,Bochet, Christian G.
-
p. 650 - 654
(2008/03/11)
-
- METHOD FOR THE PRODUCTION OF A DICARBOXYLIC ACID FROM ACRYLIC ACID
-
Disclosed is a method for producing a dicarboxylic acid of formula (I) H-OOC-(n-C4Hx)-COO-H, in which x represents 6 or 8, from acrylic acid. Said method is characterized by the fact that a) a dicarboxylic acid diester of formula (II) R1-OOC-(n-C4Hx)-COO-R2, in which x represents 6 or 8 and R1, R2 independently represent C1-, C2-, C3-, C4-alkyl, aryl, heteroaryl and can be identical or different, is reacted with acrylic acid so as to obtain a dicarboxylic acid of formula (I) and a mixture of acrylic acid ester of formula C2H3-COOR1 and C2H3-COOR2, in which R1 and R2 have the meanings mentioned above; b) the dicarboxylic acid of formula (I) obtained in step (a) is separated from the reaction mixture obtained in step (a); c) the C2H3-COOR1, C2H3-COOR2, or the mixtures thereof obtained in step (a) are dimerized so as to obtain n-butene dicarboxylic acid diester; and d) the dicarboxylic acid diester obtained in step (c) is split into the corresponding dicarboxylic acid of formula (I).
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Page/Page column 12
(2008/06/13)
-
- Aqueous biphasic oxidation: A water-soluble polyoxometalate catalyst for selective oxidation of various functional groups with hydrogen peroxide
-
A "sandwich" type polyoxometalate, Na12[(WZn 3(H2O)2][(ZnW9O34) 2], was used as an oxidation catalyst in aqueous biphasic reaction media to effect oxidation of alcohols, diols, pyridine derivatives, amines and aniline derivatives with hydrogen peroxide. The catalyst was shown by 183W NMR to be stable in aqueous solutions in the presence of H 2O2 and showed only minimal non-productive decomposition of the oxidant. Secondary alcohols were selectively oxidized to ketones, while primary alcohols tended to be oxidized to the corresponding carboxylic acids, although secondary alcohols were selectively oxidized in the presence of primary alcohols. Vicinal diols yielded carbon-carbon bond cleavage products in very high yields. Pyridine derivatives were oxidized to the respective TV-oxides, but strongly electron-withdrawing moieties inhibited the oxidation reaction. Primary amines were oxidized to the oximes, but significantly hydrolyzed in situ. Aniline derivatives were oxidized to the corresponding azoxy or nitro products depending on the substitution pattern in the aromatic ring. Catalyst recovery and recycle was demonstrated.
- Sloboda-Rozner, Dorit,Witte, Peter,Alsters, Paul L.,Neumann, Ronny
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p. 339 - 345
(2007/10/03)
-
- Novel (3,5-di-tert-butyl-2-hydroxy-phenylcarbamoyl)-alkanoic acids as potent antioxidants
-
A series of novel phenolic antioxidants of amphiphilic structure has been synthesized. Investigations into the influence of aliphatic spacer length and nature of a hydrophilic anchor on the antioxidant activity allowed elucidating certain structure requirements for the membrane-addressed antioxidant designing.
- Lodyato, Vladimir I.,Yurkova, Irina L.,Sorokin, Viktor L.,Shadyro, Oleg I.,Dolgopalets, Vladimir I.,Kisel, Mikhail A.
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p. 4253 - 4256
(2007/10/03)
-
- Wavelength-controlled orthogonal photolysis of protecting groups
-
The selective control of a chemical process by the use of an electromagnetic wave has been a challenging goal for several decades. In this article, we describe for the first time the use of a monochromatic light beam to differentiate two different reactive centers. A direct application of this concept is found in the chemistry of protecting groups. Two different photolabile protecting groups were tuned to be responsive to a specific wavelength (e.g., 254 or 420 nm). Using derivatives of the 2-nitroveratryl fragment (such as 10, sensitive at 420 nm) and 3′,5′-dimethoxybenzoin fragment (such as 4, sensitive at 254 nm), it was shown that energy transfer phenomena did not erode the selectivity. Both the inter- and the intramolecular cases were studied and showed selectivities within the synthetically useful range. Hence, we could replace the traditional chemical orthogonality by a chromatic orthogonality.
- Blanc, Aurelien,Bochet, Christian G.
-
p. 5567 - 5577
(2007/10/03)
-
- Semi-volatile and particulate emissions from the combustion of alternative diesel fuels
-
Motor vehicle emissions are a major anthropogenic source of air pollution and contribute to the deterioration of urban air quality. In this paper, we report results of a laboratory investigation of particle formation from four different alternative diesel fuels, namely, compressed natural gas (CNG), dimethyl ether (DME), biodiesel, and diesel, under fuelrich conditions in the temperature range of 800-1200°C at pressures of approximately 24 atm. A single pulse shock tube was used to simulate compression ignition (CI) combustion conditions. Gaseous fuels (CNG and DME) were exposed premixed in air while liquid fuels (diesel and biodiesel) were injected using a high-pressure liquid injector. The results of surface analysis using a scanning electron microscope showed that the particles formed from combustion of all four of the above-mentioned fuels had a mean diameter less than 0.1 μm. From results of gravimetric analysis and fuel injection size it was found that under the test conditions described above the relative particulate yields from CNG, DME, biodiesel, and diesel were 0.30%, 0.026%, 0.52%, and 0.51%, respectively. Chemical analysis of particles showed that DME combustion particles had the highest soluble organic fraction (SOF) at 71%, followed by biodiesel (66%), CNG (38%) and diesel (20%). This illustrates that in case of both gaseous and liquid fuels, oxygenated fuels have a higher SOF than non-oxygenated fuels. Motor vehicle emissions are a major anthropogenic source of air pollution and contribute to the deterioration of urban air quality. In this paper, we report results of a laboratory investigation of particle formation from four different alternative diesel fuels, namely, compressed natural gas (CNG), dimethyl ether (DME), biodiesel, and diesel, under fuelrich conditions in the temperature range of 800-1200°C at pressures of approximately 24 atm. A single pulse shock tube was used to simulate compression ignition (CI) combustion conditions. Gaseous fuels (CNG and DME) were exposed premixed in air while liquid fuels (diesel and biodiesel) were injected using a high-pressure liquid injector. The results of surface analysis using a scanning electron microscope showed that the particles formed from combustion of all four of the above-mentioned fuels had a mean diameter less than 0.1 μm. From results of gravimetric analysis and fuel injection size it was found that under the test conditions described above the relative particulate yields from CNG, DME, biodiesel, and diesel were 0.30%, 0.026%, 0.52%, and 0.51%, respectively. Chemical analysis of particles showed that DME combustion particles had the highest soluble organic fraction (SOF) at 71%, followed by biodiesel (66%), CNG (38%) and diesel (20%). This illustrates that in case of both gaseous and liquid fuels, oxygenated fuels have a higher SOF than non-oxygenated fuels.
- Sidhu, Sukh,Graham, John,Striebich, Richard
-
p. 681 - 690
(2007/10/03)
-
- A new, modulated, oxidative ring cleavage of α-nitrocycloalkanones by Oxone: Synthesis of α,ω-dicarboxylic acids and α,ω-dicarboxylic acid monomethyl esters
-
By the appropriate choice of the reaction conditions Oxone produces the ring cleavage of α-nitrocycloalkanones affording good yields of α,ω-dicarboxylic acids and α,ω-dicarboxylic acid monomethyl esters, respectively, regardless the ring size and/or the presence of an alkyl group as substituent.
- Ballini, Roberto,Curini, Massimo,Epifano, Francesco,Marcotullio, Maria Carla,Rosati, Ornelio
-
p. 1049 - 1050
(2007/10/03)
-
- Selective esterification of aliphatic nonconjugated carboxylic acids in the presence of aromatic or conjugated carboxylic acids catalysed by NiCl2.6H2O
-
Unhindered aliphatic nonconjugated carboxylic acids were esterified selectively in the presence of aromatic or conjugated acids on heating in the corresponding alcoholic solutions at reflux for 3-13 hr with 10 mol% of NiCl2.6H2O catalyst.
- Ram, Ram N.,Charles
-
p. 7335 - 7340
(2007/10/03)
-
- Les heteropolyacides comme catalyseurs bifonctionnells pour la coupure oxydante de cyclanones
-
In the presence of dioxygen, heteropolyacids "H(3+n),aq" (HPA-n; n = 1-4), react with cyclanones to afford carboxylic acids.Treatment of 2-methylcyclohexanone gives 6-oxoheptanoic acid in high yields.Reaction of cyclohexanone with "HPA-n/AcOH-H2O/O2" systems affords adipic acid, glutaric acid, succinic acid and carbon dioxide.The byproducts arise predominantly by 6-oxohexanoic acid degradation.The reaction of hydrogen peroxide with molybdenum trioxide, vanadium(V) oxide and orthophosphoric acid has been studied and the formation of HPA-n has been obtained at room temperature in a short time. - Keywords: catalytic oxidation, cycloalkanones, heteropolyacids, dioxygen
- Atlamsani, A.,Ziyad, M.,Bregeault, J. M.
-
p. 1344 - 1364
(2007/10/02)
-
- Pig liver esterase catalyzed hydrolyses of diesters. A new route to the syntheses of achiral half-esters
-
Pig liver esterase catalyzed hydrolyses of diesters of alkanes, aromatic and heterocyclic compounds gave high yields of the corresponding half-esters under mild reaction conditions.
- Ager,Prakash
-
p. 739 - 742
(2007/10/02)
-
- Enzymatic Preparation of Alkanedicarboxylic Acid Monoesters
-
Hydrolysis of alkanedicarboxylic acid dimethyl esters using esterase from Pseudomonas putida MR-2068 gave exclusively pure monoesters.Hydrolytic activities were dependent on the carbon chain length of the substrates.This esterase also catalyzed enantio- and regio-selective hydrolysis of α-methylalkanedicarboxylic acid dimethyl esters.
- Ozaki, Eiji,Uragaki, Toshitaka,Sakashita, Keiichi,Sakimae, Akihiro
-
p. 539 - 540
(2007/10/03)
-
- Enzyme-assisted Preparation of Pure Alkanedicarboxylic Acid Monoesters: Chain-length Dependence of Porcine Liver Esterase (PLE)-catalysed Hydrolyses
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Porcine liver esterase (PJE)-catalysed hydrolyses of alkanedicarboxylic esters MeO2C-(CH2)n-CO2Me lead exclusively to pure monoesters if n 8.Using the active site model for PLE an interpretation of these surprising observations is attempted.
- Lobell, Mario,Schneider, Manfred P.
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p. 1713 - 1714
(2007/10/02)
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- Enzymic Polymerisation of an Unactivated Diol/Diacud System
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The polyesterification of adipic acid and butane-1,4-diol by a commercial lipase (Lipozyme IM-20) has been studied using a two-chamber reactor and molecular sieve as a dehydrating agent.The lower oligomeric products were identified and a low-disperisity polyester averaging 20 repeat units was produced.
- Binns, Falmai,Roberts, Stanley M.,Taylor, Alan,Williams, Charles F.
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p. 899 - 904
(2007/10/02)
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- Homoenolic radical derived from propionic acid: A versatile reagent for the radical version of the Michael reaction
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The homoenolic radical, derived from 3-iodopropionic acid (1) by reaction with in situ generated tributyltin hydride, undergoes clean carbon-carbon forming reaction with electrophilic olefins (2) yielding functionalized acids (3).
- Foubelo,Lloret,Yus
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p. 9531 - 9536
(2007/10/02)
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- Preparation of adipic acid
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Adipic acid is prepared by a process which comprises the following steps: (a) Hydroformylation of a pentenoic ester by reaction with carbon monoxide and hydrogen at elevated temperatures and under superatmospheric pressure in the presence of a cobalt carbonyl or rhodium carbonyl complex with formation of a mixture of 5-, 4- and 3-formylvaleric esters, (b) isolation of the 5-formylvaleric ester from the resulting mixture of 5-, 4- and 3-formylvaleric esters, a mixture essentially consisting of 4- and 3-formylvaleric esters remaining, (c) dehydrocarbonylation of the mixture consisting essentially of 4- and 3-formylvaleric esters in the presence of one or more elements of subgroup 8 of the Periodic Table at from 50° to 400° C. with formation of pentenoic esters, and recycling of the latter to stage (a) for hydroformylation, (d) oxidation of the 5-formylvaleric ester from stage (b) with molecular oxygen or a gas containing molecular oxygen to give a monoester of adipic acid, and (e) hydrolysis of the monoester of adipic acid to give adipic acid.
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- Process for the preparation of carboxylic acid methyl esters
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A process for the preparation of methyl carboxylates by the reaction of mono or dicarboxylic acids having more than 5 carbon atoms and methanol in the presence of acidic catalysts at temperatures from 100° to 150° C. and below the boiling point of the carboxylates being produced.
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- Preparation of cyclic ketones
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Cyclic ketones of the formula STR1 where n is an integer from 4 to 6, are prepared by converting an aliphatic dicarboxylate of the formula where n has the above meaning, R1 and R2 are each alkyl, cycloalkyl, aralkyl or aryl and R2 may furthermore be hydrogen, at from 150° to 450° C. over a solid oxide catalyst.
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- Methylation of Alcohols, Phenols, and Carboxylic Acids, and Selective Monomethylation of Diols and Dicarboxylic Acids with Dimethyl Sulfate by Use of Alumina
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Alcohols in cyclohexane give their methyl ethers in high yields by the use of a combination of dimethyl sulfate and alumina.Some diols and dicarboxylic acids adsorbed on alumina react with dimethyl sulfate and produce the corresponding monomethyl ethers and esters in high selectivities.
- Ogawa, Haruo,Ichimura, Youko,Chihara, Teiji,Teratani, Shousuke,Taya, Kazuo
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p. 2481 - 2484
(2007/10/02)
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- DYE-SENSITIZED PHOTO-OXYGENATION OF 1,2-CYCLOHEXANEDIONES
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The dye-sensitized photo-oxygenation of the enols of 1,2-cyclohexanedione (1) has been carried out in various solvents at -70 - 40 deg C.Singlet oxygen is involved in the reaction as evidenced by quenching and rate enhancement observed in deuterated methanol.The reaction proceeds by an ene reaction with singlet oxygen to afford the hydroperoxide, 4, which closes to a five-membered endoperoxide, 5, as a major path or to dioxetane (6) as a minor one.The endoperoxide, 5, decomposed to 5-oxoalkanoic acid (2) with evolution of carbon monoxide or was trapped by the solvent (MeOH or EtOH) to give methyl or ethyl 5-carboxy-2-hydroxypentanoate (3).Competition between the enol of 3-methyl-1,2-cyclohexanedione (1a) and 2,3-dimethyl-2-butene (TME) has shown that the enol is as reactive as TME toward singlet oxygen.
- Utaka, Masanori,Nakatani, Manabu,Takeda, Akira
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p. 2163 - 2168
(2007/10/02)
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- Synthesis of Tetrahydrofuranic Acids Substituted in Position 2 and 5
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A synthesis of the 3,6-epoxyalkane diacids 9a-d previously detected in human urine is described.
- Kern, Werner,Spiteller, Gerhard
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p. 1168 - 1174
(2007/10/02)
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- Preparation of pure monoesters of adipic acid
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Pure monoesters of adipic acid are prepared by a process in which (a) a pentenoate is reacted with carbon monoxide and hydrogen at from 90° to 140° C. and under from 5 to 300 bar in the presence of a carbonyl complex of cobalt or of rhodium, and a 5-formylvalerate is separated off, and (b) the 5-formylvalerate thus obtained is oxidized with molecular oxygen, or with a gas containing this, at from 20° to 100° C. under from 1 to 10 bar.
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- SELECTIVE MONOMETHYL ESTERIFICATION OF DICARBOXYLIC ACIDS BY USE OF MONOCARBOXYLATE CHEMISORPTION ON ALUMINA.
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The application of alumina as a solid support affords a new procedure for selective reactions. Although it is difficult to obtain monoesters in the esterification of dicarboxylic acids by conventional methods, dicarboxylic acids adsorbed on alumina selectively form the monoesters. Terephthalic acid (1), isophthalic acid, cis- and trans-1,4-cyclohexanedicarboxylic acids, and aliphatic dicarboxylic acids give the corresponding monomethyl esters quantitatively with diazomethane. On the basis of these results, the authors suggest that dicarboxylic acids are adsorbed on alumina through one of their carboxyl groups, and the carboxyl group not adsorbed on the alumina is esterified selectively. Selective monomethyl esterification of phthalic acid is not successful on alumina, probably as a consequence of the close proximity of the two carboxyl groups and the forced orientation of the second group when one is adsorbed.
- Ogawa,Chihara,Taya
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p. 1365 - 1369
(2007/10/02)
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- A CONVENIENT PREPARATION OF METHYL ESTERS FROM CARBOXYLIC ACIDS
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A facile procedure for the preparation of methyl esters from carboxylic acids under neutral conditions is described.
- Mohacsi, Erno
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p. 453 - 456
(2007/10/02)
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- Oxidation of Some 2-Methoxyphenols with Chlorous Acid
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Oxidation of 3-ethoxy-4-hydroxy-, 4-hydroxy-3-methoxy-5-methyl-, 3-chloro-4-hydroxy-5-methoxy-, and 2-hydroxy-3-methoxybenzaldehyde with chlorous acid gives, by oxidative aromatic ring cleavage between the oxygen-bearing carbon atoms, derivatives of (2Z, 4Z)-2,4-hexadienedioic acid in low yields.Chlorous acid oxidation of 2-methoxyphenol and 3-hydroxy-4-methoxybenzaldehyde yields methoxy-1,4-benzoquinone and 5,5-dichloro-6,6-dihydroxy-2-methoxy-2-cyclohexene-1,4-dione, respectively.The hydrate as well as the corresponding methyl hemiacetal undergoes base-catalyzed ring contraction to a derivative of 1-hydroxy-4-oxo-2-cyclopentenecarboxylic acid.The kinetics of the ring contraction of the hydrate was investigated in aqueous solutions in the pH range 1.15-3.65, where the rearrangement appears to be subject to specific base catalysis.
- Jaroszewski, Jerzy W.
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p. 2013 - 2018
(2007/10/02)
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- Conjugate, Homoconjugate, and 1,2-Additions of Acetylene Nucleophiles and their Application to Prostaglandin Synthesis
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1-Acylcyclopent-1-enes (10) and (11) undergo 1,4- and 1,2-addition reactions with various alkynylalane reagents at ambient temperatures.Homoconjugate additions of alkynylalanes to endo-3-t-butyldimethylsilyloxytricyclo2,7>heptan-6-one (12) occur to give 7-anti-alkynylbicycloheptanones (24) and (25). 1-Lithioalk-1-ynes can undergo conjugate additions when the reagent is solvated with hexamethylphosphoric triamide. These reactions, designed to provide an approach to prostanoic acid derivatives and their intermediates, avoid the use of low temperatures for conjugate additions.
- Newton, Roger F.,Reynolds, Derek P.,Greenwood, John,Scheinmann, Feodor
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p. 2346 - 2352
(2007/10/02)
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- Process for producing sebacic acid
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Sebacic acid is produced from adipic acid by half esterifying adipic acid with methanol to produce monomethyl adipate, carrying out electrolytic condensation of the monomethyl adipate in a methanol solution containing an alkali metal salt of the monomethyl adipate to give an electrolytic solution containing dimethyl sebacate, treating the electrolytic solution by a combination of water treatment and anion exchange treatment or a combination of cation exchange treatment and anion exchange treatment to remove the monomethyl adipate and its alkali metal salt from the electrolytic solution, separating the dimethyl sebacate, and hydrolyzing the dimethyl sebacate to give sebacic acid.
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