- Electrophilic aromatic substitution of arenes with CO2 mediated by R3SiB(C6F5)4
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The FriedelCrafts- type carboxylation of arenes has been achieved by activating CO2 with silylium borates. The reaction exhibits broader substrate applicability than does our previously reported AlX3/R 3SiX-mediated carboxylation.
- Konno, Megumi,Chiba, Masafumi,Nemoto, Koji,Hattori, Tetsutaro
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Read Online
- An efficient chromium(iii)-catalyzed aerobic oxidation of methylarenes in water for the green preparation of corresponding acids
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A highly efficient method to oxidize methylarenes to their corresponding acids with a reusable Cr catalyst was developed. The reaction can be carried out in water with 1 atm oxygen and K2S2O8as cooxidants, proceeds under green and mild conditions, and is suitable for the oxidation of both electron-deficient and electron-rich methylarenes, including heteroaryl methylarenes, even at the gram level. The excellent result, together with its simplicity of operation and the ability to continuously reuse the catalyst, makes this new methodology environmentally benign and cost-effective. The generality of this methodology gives it the potential for use on an industrial scale. Differing from the accepted oxidation mechanism of toluene, GC-MS studies and DFT calculations have revealed that the key benzyl alcohol intermediate is formed under the synergetic effect of the chromium and molybdenum in the Cr catalyst, which can be further oxidized to afford benzaldehyde and finally benzoic acid.
- Jiang, Feng,Liu, Shanshan,Wei, Yongge,Yan, Likai,Yu, Han,Zhao, Wenshu
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supporting information
p. 12413 - 12418
(2021/09/28)
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- Method for preparing 2, 4, 6-trimethylbenzoic acid from mesitylene and carbon dioxide
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The invention discloses a method for preparing 2, 4, 6-trimethylbenzoic acid from mesitylene and carbon dioxide. The method comprises the step of synthesizing 2, 4, 6-trimethylbenzoic acid by taking mesitylene as a raw material, lewis acid as a catalyst and carbon dioxide as a carbon source under certain pressure and temperature. Oxidants such as potassium permanganate are not used. The method has the highest atom utilization rate of the synthesis reaction, and has atom economy and good industrial application prospect.
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Paragraph 0019-0030
(2021/04/17)
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- Highly efficient oxidation of alcohols to carboxylic acids using a polyoxometalate-supported chromium(iii) catalyst and CO2
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Direct catalytic oxidation of alcohols to carboxylic acids is very attractive, but economical catalysis systems have not yet been well established. Here, we show that a pure inorganic ligand-supported chromium compound, (NH4)3[CrMo6O18(OH)6] (simplified as CrMo6), could be used to effectively promote this type of reaction in the presence of CO2. In almost all cases, oxidation of various alcohols (aromatic and aliphatic) could be achieved under mild conditions, and the corresponding carboxylic acids can be achieved in high yield. The chromium catalyst 1 can be reused several times with little loss of activity. Mechanism study and control reactions demonstrate that the acidification proceeds via the key oxidative immediate of aldehydes.
- Han, Sheng,Wang, Ying,Wei, Yongge,Wu, Zhikang,Yu, Han
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p. 3150 - 3154
(2020/06/19)
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- Pd(II) porphyrins: Synthesis, singlet oxygen generation and photoassisted oxidation of aldehydes to carboxilic acids
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The synthesis and spectral studies of A3B and A2B2 type porphyrins and their Pd(II) complexes are reported. The meso-positions on porphyrin macrocycle are substituted with pentafluorophenyl and N-butylcarbazole or triphenylamine groups. Pd(II) porphyrins displayed decent phosphorescence ～670 nm and are able to produce singlet oxygen by type II pathway, after photoirradiation. The calculated singlet oxygen quantum yields for Pd(II) porphyrins are (ΦΔ = 30%–63%). The catalytic application of Pd(II) porphyrins towards photoassisted aerobic oxidation of aromatic aldehydes to carboxylic acids is demonstrated.
- Pandey, Vijayalakshmi,Jain, Drishti,Pareek, Nitesh,Gupta, Iti
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- Two-Phase Reactions in Microdroplets
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Improved two phase chemical reactions (liquid-liquid or liquid-gas) are provided by forming microdroplets of either or both liquid reagents and configuring the reaction as a collision between the microdroplet reagent and the other reagent. We have found that this approach can provide high reaction yields in short times (1 s) without the use of a phase transfer catalyst.
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Paragraph 0074; 0083; 0084
(2019/12/01)
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- Preparation method of 2,4,6-trimethyl benzoic acid
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The invention provides a preparation method of 2,4,6-trimethyl benzoic acid. The preparation method of the 2,4,6-trimethyl benzoic acid comprises the following steps that step (1) a Friedel-Crafts reaction is carried out, specifically, 1,3,5-trimethylbenzene is used as a raw material and subjected to the Friedel-Crafts reaction with trichloro-acetic chloride under the action of a catalyst; and step (2) a hydrolysis reaction is carried out, specifically, a product obtained in the step (1) is hydrolyzed under the acidic condition to obtain the 2,4,6-trimethyl benzoic acid. The preparation methodof the 2,4,6-trimethyl benzoic acid has the advantages of high reaction conversion, less pollution, improved yield and purity of the product and the like, and is suitable for industrial production.
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Paragraph 0025-0030
(2019/11/13)
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- Sodium Methyl Carbonate as an Effective C1 Synthon. Synthesis of Carboxylic Acids, Benzophenones, and Unsymmetrical Ketones
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Reported is the synthesis of carboxylic acids, symmetrical ketones, and unsymmetrical ketones with selectivity achieved by exploiting the differential reactivity of sodium methyl carbonate with Grignard and organolithium reagents.
- Hurst, Timothy E.,Deichert, Julie A.,Kapeniak, Lucas,Lee, Roland,Harris, Jesse,Jessop, Philip G.,Snieckus, Victor
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supporting information
p. 3882 - 3885
(2019/06/07)
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- Carboxylation of Aryl Triflates with CO2 Merging Palladium and Visible-Light-Photoredox Catalysts
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We report herein a visible-light-promoted, highly practical carboxylation of readily accessible aryl triflates at ambient temperature and a balloon pressure of CO2 by the combined use of palladium and photoredox Ir(III) catalysts. Strikingly, the stoichiometric metallic reductant is replaced by a nonmetallic amine reductant providing an environmentally benign carboxylation process. In addition, one-pot synthesis of a carboxylic acid directly from phenol and modification of estrone and concise synthesis of pharmaceutical drugs adapalene and bexarotene have been accomplished via late-stage carboxylation reaction. Furthermore, a parallel decarboxylation-carboxylation reaction has been demonstrated in an H-type closed vessel that is an interesting concept for the strategic sector. Spectroscopic and spectroelectrochemical studies indicated electron transfer from the Ir(III)/DIPEA combination to generate aryl carboxylate and Pd(0) for catalytic turnover.
- Bhunia, Samir Kumar,Das, Pritha,Nandi, Shantanu,Jana, Ranjan
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supporting information
p. 4632 - 4637
(2019/06/27)
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- Palladium-Catalyzed Visible-Light-Driven Carboxylation of Aryl and Alkenyl Triflates by Using Photoredox Catalysts
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A visible-light-driven carboxylation of aryl and alkenyl triflates with CO2 is developed by using a combination of Pd and photoredox catalysts. This reaction proceeds under mild conditions and can be applied to a wide range of substrates including acyclic alkenyl triflates.
- Shimomaki, Katsuya,Nakajima, Tomoya,Caner, Joaquim,Toriumi, Naoyuki,Iwasawa, Nobuharu
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supporting information
p. 4486 - 4489
(2019/06/24)
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- Palladium complex containing diphosphine m-carborane ligand as well as preparation and application of palladium complex
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The invention relates to a palladium complex containing a diphosphine m-carborane ligand as well as a preparation and an application of the palladium complex. The preparation method of the palladium complex comprises the following steps of 1) adding an n-BuLi solution into a m-carborane solution, and then reacting for 30-60 minutes at a room temperature; 2) adding diphenyl phosphorus chloride, andreacting for 3-6 h at the room temperature; and 3) adding PdCl2, reacting at the room temperature for 3-5 hours, and carrying out post-treatment to obtain the palladium complex. The palladium complexis used for catalyzing the reaction of halohydrocarbon with carbon dioxide to synthesize carboxylic acid. Compared with the prior art, the synthesis process is simple and green, and has the excellentselectivity and high yield; the palladium complex has the stable physicochemical properties and is used as the catalyst, the halogenated hydrocarbon is used as a substrate, the palladium complex andthe halogenated hydrocarbon are jointly dissolved in toluene, and the carbon dioxide is introduced at the normal pressure for reaction, so that the corresponding carboxylic acid can be synthesized athigh yield.
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Paragraph 0059-0062
(2019/12/02)
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- Substituted arene formyl chloride synthesis method
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The invention relates to the technical field of synthesis of fine chemical intermediates, particularly to a substituted arene formyl chloride synthesis method, which comprises: carrying out a reactionon substituted arene formic acid and substituted trichloromethyl arene under the action of a catalyst 3 to obtain the substituted arene formyl chloride. According to the present invention, the synthesis method has characteristics of inexpensive and easily-available raw materials, short process route, good production safety, easy separation of catalyst, high atomic utilization rate, less waste acid discharge, simple post-treatment, high yield and good quality, and is suitable for industrial continuous production.
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Paragraph 0089; 0090; 0093; 0094; 0097; 0098
(2019/04/18)
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- Preparation method of phenyl bis (2,4,6-trimethylbenzoyl) phosphine oxide
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The invention provides a preparation method of phenyl bis (2,4,6-trimethylbenzoyl) phosphine oxide. The preparation method comprises the following steps: using phenyl phosphorus dichloride as an initial raw material, under the protection of nitrogen, adopting a catalyst (the catalyst is a mixture of potassium tert-butoxide and serine) to replace chlorine with powdery metal sodium, carrying out reduction under a weak alkaline condition, and carrying out condensation and oxidation reaction with 2,4,6-trimethylbenzoyl chloride to prepare a phenyl bis (2,4,6-trimethylbenzoyl) phosphine oxide product. The preparation method of phenyl bis (2,4,6-trimethylbenzoyl) phosphine oxide has better catalytic effect and higher yield; and the metal sodium is prepared into powder in a toluene solvent, and all reaction processes are carried out under the protection of nitrogen, so that the safety is high.
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Paragraph 0032; 0035; 0039; 0041; 0045; 0047
(2019/10/01)
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- Continuous Platform to Generate Nitroalkanes On-Demand (in Situ) Using Peracetic Acid-Mediated Oxidation in a PFA Pipes-in-Series Reactor
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The synthetic utility of the aza-Henry reaction can be diminished on scale by potential hazards associated with the use of peracid to prepare nitroalkane substrates and the nitroalkanes themselves. In response, a continuous and scalable chemistry platform to prepare aliphatic nitroalkanes on-demand using the oxidation of oximes with peracetic acid and direct reaction of the nitroalkane intermediate in an aza-Henry reaction is reported. A uniquely designed pipes-in-series plug-flow tube reactor addresses a range of process challenges, including stability and safe handling of peroxides and nitroalkanes. The subsequent continuous extraction generates a solution of purified nitroalkane, which can be directly used in the following enantioselective aza-Henry chemistry to furnish valuable chiral diamine precursors with high selectivity, thus completely avoiding isolation of the potentially unsafe low-molecular-weight nitroalkane intermediate. A continuous campaign (16 h) established that these conditions were effective in processing 100 g of the oxime and furnishing 1.4 L of nitroalkane solution.
- Tsukanov, Sergey V.,Johnson, Martin D.,May, Scott A.,Kolis, Stanley P.,Yates, Matthew H.,Johnston, Jeffrey N.
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p. 971 - 977
(2018/08/28)
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- Method for synthesizing benzoic acid compound from benzyl alcohol compound by ultrasonic-assisted oxidation
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The invention belongs to the field of synthesis of organic intermediates, and specifically discloses an ultrasonic-assisted synthesis method for a benzoic acid compound. The method comprises the following step: promoting air oxidation of benzyl alcohol by using diethylene glycol dimethyl ether under an ultrasonic-assisted action so as to obtain the benzoic acid compound, wherein a benzyl alcohol raw material is benzyl alcohol, or a benzoic acid derivative containing one to five substituents at different positions on the benzene ring of benzyl alcohol; and a reaction accelerator is the diethylene glycol dimethyl ether. The method provided by the invention has the advantages of easily-available raw materials, simple and convenient reaction conditions, short reaction time, greenness, energy conservation, high reaction selectivity and yield, excellent compatibility of substrate functional groups, and high application value.
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Paragraph 0162; 0163
(2018/09/29)
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- An Efficient Aerobic Oxidation Protocol of Aldehydes to Carboxylic Acids in Water Catalyzed by an Inorganic-Ligand-Supported Copper Catalyst
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A method for the aerobic oxidation of aldehydes to carboxylic acids in water by using an inorganic-ligand-supported copper catalyst was developed. This method was performed with the use of atmospheric oxygen as the sole oxidant under extremely mild aqueous conditions, and furthermore, a wide range of aldehydes with various functional groups were tolerated. The copper catalyst could be recycled and used in successive reactions at least six times without any appreciable degradation in performance. This method is operationally simple and avoids the use of high-costing, toxic, air/moisture-sensitive, and commercially unavailable organic ligands. The generality of this method gives it potential to be used on the industrial scale.
- Yu, Han,Ru, Shi,Zhai, Yongyan,Dai, Guoyong,Han, Sheng,Wei, Yongge
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p. 1253 - 1257
(2018/02/16)
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- Preparative microdroplet synthesis of carboxylic acids from aerobic oxidation of aldehydes
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Single liquid-phase and liquid-liquid phase reactions in microdroplets have shown much faster kinetics than that in the bulk phase. This work extends the scope of microdroplet reactions to gas-liquid reactions and achieves preparative synthesis. We report highly efficient aerobic oxidation of aldehydes to carboxylic acids in microdroplets. Molecular oxygen plays two roles: (1) as the sheath gas to shear the aldehyde solution into microdroplets, and (2) as the sole oxidant. The dramatic increase of the surface-area-to-volume ratio of microdroplets compared to bulk solution, and the efficient mixing of gas and liquid phases using spray nozzles allow effective mass transfer between aldehydes and molecular oxygen. The addition of catalytic nickel(ii) acetate is shown to accelerate further microdroplet reactions of this kind. We show that aliphatic, aromatic, and heterocyclic aldehydes can be oxidized to the corresponding carboxylic acids in a mixture of water and ethanol using the nickel(ii) acetate catalyst, in moderate to excellent yields (62-91%). The microdroplet synthesis is scaled up to make it preparative. For example, aerobic oxidation of 4-tert-butylbenzaldehyde to 4-tert-butylbenzoic acid was achieved at a rate of 10.5 mg min-1 with an isolated product yield of 66%.
- Yan, Xin,Lai, Yin-Hung,Zare, Richard N.
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p. 5207 - 5211
(2018/06/21)
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- A biocatalytic method for the chemoselective aerobic oxidation of aldehydes to carboxylic acids
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Herein, we present a study on the oxidation of aldehydes to carboxylic acids using three recombinant aldehyde dehydrogenases (ALDHs). The ALDHs were used in purified form with a nicotinamide oxidase (NOx), which recycles the catalytic NAD+ at the expense of dioxygen (air at atmospheric pressure). The reaction was studied also with lyophilised whole cell as well as resting cell biocatalysts for more convenient practical application. The optimised biocatalytic oxidation runs in phosphate buffer at pH 8.5 and at 40 °C. From a set of sixty-one aliphatic, aryl-Aliphatic, benzylic, hetero-Aromatic and bicyclic aldehydes, fifty were converted with elevated yield (up to >99%). The exceptions were a few ortho-substituted benzaldehydes, bicyclic heteroaromatic aldehydes and 2-phenylpropanal. In all cases, the expected carboxylic acid was shown to be the only product (>99% chemoselectivity). Other oxidisable functionalities within the same molecule (e.g. hydroxyl, alkene, and heteroaromatic nitrogen or sulphur atoms) remained untouched. The reaction was scaled for the oxidation of 5-(hydroxymethyl)furfural (2 g), a bio-based starting material, to afford 5-(hydroxymethyl)furoic acid in 61% isolated yield. The new biocatalytic method avoids the use of toxic or unsafe oxidants, strong acids or bases, or undesired solvents. It shows applicability across a wide range of substrates, and retains perfect chemoselectivity. Alternative oxidisable groups were not converted, and other classical side-reactions (e.g. halogenation of unsaturated functionalities, Dakin-Type oxidation) did not occur. In comparison to other established enzymatic methods such as the use of oxidases (where the concomitant oxidation of alcohols and aldehydes is common), ALDHs offer greatly improved selectivity.
- Knaus, Tanja,Tseliou, Vasilis,Humphreys, Luke D.,Scrutton, Nigel S.,Mutti, Francesco G.
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supporting information
p. 3931 - 3943
(2018/09/11)
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- Method for preparing aromatic acid by direct carboxylation of CO2
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The invention discloses a method for preparing aromatic acid by direct carboxylation of CO2. The method comprises the following steps: (1) adding aromatic hydrocarbon, organic alkali and lewis acid into a high pressure reaction kettle under an inert gas atmosphere, then feeding CO2 gas into the high pressure reaction kettle for reaction, and obtaining reaction liquid with aromatic acid at the endof the reaction; (2) adding water into the reaction liquid obtained in the step (1), then extracting the aromatic acid in the reaction liquid with an extracting agent to enable the aromatic acid in the reaction liquid to enter an extracting phase, separating the extracting phase from raffinate, and concentrating the extracting phase to obtain the aromatic acid. According to the method, complicatedpreparation of ionic liquid is avoided, and organic alkali is timely neutralized with halogen hydride produced by the reaction, so that the balance moves rightwards; at the end of the reaction, the organic alkali also can be recycled through alkali treatment. The method has the advantages of simple operation, mild conditions, green process, low cost and the like, and is expected to be applied toindustrial production.
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Paragraph 0043; 0044; 0045
(2018/05/16)
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- Acceptorless and Base-free Dehydrogenation of Cyanohydrin with (η6-Arene)halide(Bidentate Phosphine)ruthenium(II) Complex
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Ruthenium-catalyzed dehydrogenation of cyanohydrins under acceptorless and base-free conditions was demonstrated for the first time in the synthesis of acyl cyanide. As opposed to the thermodynamically preferred elimination of hydrogen cyanide, the dehydrogenation of cyanohydrins could be kinetically controlled with ruthenium (II) bidentate phosphine complexes. The effects of the arene, phosphine ligands and counter anions were investigated in regard to catalytic activity and selectivity. Selective dehydrogenation can occur via β-hydride elimination with the experimentally observed [(alkoxide)Ru] complex. (Figure presented.).
- Kim, Kicheol,Moeljadi, Adhitya Mangala Putra,Hirao, Hajime,Hong, Soon Hyeok
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supporting information
p. 3292 - 3298
(2017/09/06)
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- Iodine catalyzed oxidation of alcohols and aldehydes to carboxylic acids in water: A metal-free route to the synthesis of furandicarboxylic acid and terephthalic acid
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A metal-free iodine/NaOH-catalyzed oxidation of alcohols and aldehydes has been developed for the practical synthesis of a wide range of carboxylic acids using water as the solvent. This transformation involves dehydrogenation of an alcohol, followed by a fast attack of water on an aldehyde. This method is mostly free from chromatographic purification, which makes it suitable for large-scale synthesis. The iodine species formed during the reaction as the active oxidation catalyst has been deduced as IO2- by control experiments. We also demonstrate a 10 gram scale synthesis of furandicarboxylic acid (FDCA) from HMF in good yield using our method.
- Hazra, Susanta,Deb, Mayukh,Elias, Anil J.
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supporting information
p. 5548 - 5552
(2017/12/06)
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- Silver-Catalyzed Dehydrogenative Synthesis of Carboxylic Acids from Primary Alcohols
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A simple silver-catalyzed protocol has been developed for the acceptorless dehydrogenation of primary alcohols into carboxylic acids and hydrogen gas. The procedure uses 2.5 % Ag2CO3 and 2.5–3 equiv of KOH in refluxing mesitylene to afford the potassium carboxylate which is then converted into the acid with HCl. The reaction can be applied to a variety of benzylic and aliphatic primary alcohols with alkyl and ether substituents, and in some cases halide, olefin, and ester functionalities are also compatible with the reaction conditions. The dehydrogenation is believed to be catalyzed by silver nanoparticles that are formed in situ under the reaction conditions.
- Ghalehshahi, Hajar Golshadi,Madsen, Robert
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p. 11920 - 11926
(2017/09/07)
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- An Efficient Iron(III)-Catalyzed Aerobic Oxidation of Aldehydes in Water for the Green Preparation of Carboxylic Acids
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The first example of a heterogeneous iron(III)-catalyzed aerobic oxidation of aldehydes in water was developed. This method utilizes 1 atmosphere of oxygen as the sole oxidant, proceeds under extremely mild aqueous conditions, and covers a wide range of various functionalized aldehydes. Chromatography is generally not necessary for product purification. Its operational simplicity, gram-scale oxidation, and the ability to successively reuse the catalyst, make this new methodology environmentally benign and cost effective. The generality of this methodology gives it the potential to be used on an industrial scale.
- Yu, Han,Ru, Shi,Dai, Guoyong,Zhai, Yongyan,Lin, Hualin,Han, Sheng,Wei, Yongge
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p. 3867 - 3871
(2017/03/27)
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- Harnessing the Reactivity of Iridium Hydrides by Air: Iridium-Catalyzed Oxidation of Aldehydes to Acids in Water
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An iridium-catalyzed oxidation of aldehydes to acids was realized by using air as the oxidant and water as the solvent in the presence of base. Interestingly, the same type of catalysts were also used for the reduction of aldehydes under acidic conditions. A common iridium hydride intermediate is proposed for both redox reactions. The oxidation has a number of advantages such as high yields, great functionality tolerance, and easy purification without chromatography.
- Yang, Zhanhui,Luo, Renshi,Zhu, Zhongpeng,Yang, Xuerong,Tang, Weiping
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supporting information
p. 4095 - 4098
(2017/11/21)
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- A carbon dioxide by the method of preparing the arylcarboxylic acid
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The invention discloses a method for preparing arylformic acid from carbon dioxide, belonging to the technical field of comprehensive utilization of carbon dioxide. The method comprises the following concrete steps: reacting sodium arylsulfinate with CO2 (0.1MPa) in a Schlenk tube subjected to dehydration and deoxidation treatment in the presence of a catalytic system comprising copper salt, a nitrogen-containing ligand and alkali, and acidifying reaction liquid by a diluted hydrochloric acid solution to obtain arylformic acid. A catalyst used in the catalytic system is simple and easily available, high in catalytic activity, low in consumption, relatively mild in reaction condition and good in universality on sodium arylsulfinate. Raw materials in the preparation method disclosed by the invention are easily available, the reaction condition is mild, a reaction substrate is good in universality, the reaction time is short, the yield of a target product is high, and the reaction operation and the post-treatment process are simple.
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Paragraph 0050-0051
(2017/03/22)
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- Chemoselective Transformation of Diarylethanones to Arylmethanoic Acids and Diarylmethanones and Mechanistic Insights
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The chemoselective transformation of diarylethanones via either aerobic oxidative cleavage to give arylmethanoic acids or tandem aerobic oxidation/benzilic acid rearrangement/decarboxylation to give diarylmethanones has been developed. The transformation is controllable and applicable to a broad spectrum of substrates and affords the desired products in good to excellent yields. Mechanistic insights with control reactions, 1H NMR tracking, and single-crystal X-ray diffraction reveal a complex mechanistic network in which two common intermediates, α-ketohydroperoxide and diarylethanedione, and three plausible pathways are proposed and verified. These pathways are interlinked and can be switched reasonably by changing the reaction conditions. This method enables scalable synthesis and access to a number of valuable compounds, including vitamin B3, diphenic acid, and the nonsteroidal anti-inflammatory drug ketoprofen. The present protocol represents a step forward in exploiting complex mechanistic networks to control reaction pathways, achieving divergent syntheses from the same class of starting materials.
- Wang, Xing,Chen, Rui-Xi,Wei, Zeng-Feng,Zhang, Chen-Yang,Tu, Hai-Yang,Zhang, Ai-Dong
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p. 238 - 249
(2016/01/15)
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- DMF-mediated deprotection of bulky silyl esters under neutral and fluoride-free conditions
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Bulky TBDPS and TIPS carboxylic esters were efficiently cleaved by a green and mild protocol using only DMF-H2O (20:1) at 70 °C. The neutral conditions tolerate various common acid- and base-labile functionalities, including alkyl and aryl silyl ethers.
- Chen, Bo,Sun, Hui-Xia,Qin, Jian-Feng,Wang, Bing
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p. 253 - 255
(2016/01/12)
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- Synthetic process of 2,4,6-trimethyl benzoic acid
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The invention discloses a synthetic process of 2,4,6-trimethyl benzoic acid; 2,4,6-trimethyl benzoic acid can be used as an intermediate for dyes, insecticides, medicines and photoinitiators, and can be used for synthesizing trimethyl benzoyl chloride, a hardening agent for polyepoxide and a photoinitiator for a polymer. The synthetic process successively includes an acylation reaction, a chloroform reaction and a hydrolysis reaction and includes the following steps: (1), acylation reaction: taking sym-trimethylbenzene and chloroacethyl chloride as acylation raw materials, adopting an acylation catalyst, heating, filtering and acidifying the filtrate to prepare 2,4,6-trimethyl chloroacetophenone; (2), chloroform reaction: with the product obtained in the step (1) and sodium hypochlorite as raw materials, adopting a quaternary ammonium salt as a phase transfer catalyst, heating, carrying out a reduction reaction to prepare 2,4,6-trimethyl benzoic acid; and (3), hydrolysis reaction: carrying out extraction liquid dividing, acid neutralization and re-crystallization of the product obtained in the step (2).
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Paragraph 0011
(2017/03/08)
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- Cobalt- and Nickel-Catalyzed Carboxylation of Alkenyl and Sterically Hindered Aryl Triflates Utilizing CO2
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A highly efficient cobalt-catalyzed reductive carboxylation reaction of alkenyl trifluoromethanesulfonates (triflates) has been developed. By employing Mn powder as a reducing reagent under 1 atm pressure of CO2 at room temperature, diverse alkenyl triflates can be converted to the corresponding α,β-unsaturated carboxylic acids. Moreover, the carboxylation of sterically hindered aryl triflates proceeds smoothly in the presence of a nickel or cobalt catalyst.
- Nogi, Keisuke,Fujihara, Tetsuaki,Terao, Jun,Tsuji, Yasushi
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p. 11618 - 11623
(2015/12/01)
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- Copper(I)-Catalyzed Desulfinative Carboxylation of Sodium Sulfinates using Carbon Dioxide
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A copper(I)-catalyzed desulfinative carboxylation of sodium sulfinates using carbon dioxide has been developed. This reaction showed wide functional group tolerance. A series of sodium aryl- and alkenylsulfinates could be converted into the corresponding carboxylic acids in good to excellent yields. Additionally, the reaction mechanism was studied by in situ NMR analysis and isotopic labeling experiments.
- Sun, Song,Yu, Jin-Tao,Jiang, Yan,Cheng, Jiang
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supporting information
p. 2022 - 2026
(2015/06/23)
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- Photoinduced reductive perfluoroalkylation of phosphine oxides: synthesis of P-perfluoroalkylated phosphines using TMDPO and perfluoroalkyl iodides
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A photoinduced reaction between TMDPO (diphenyl(2,4,6-trimethylbenzoyl)-phosphine oxide) and perfluoroalkyl iodides successfully affords P-(perfluoroalkyl)diphenylphosphines as promising ligands for recyclable catalysts. Interestingly, the perfluoroalkylation reaction involves the reduction of phosphorus(v) compounds to phosphorus(iii) species. The advantages of the present reaction include the use of an air-stable phosphorus source and good yields of P-perfluoroalkylphosphines in short reaction times.
- Sato, Yuki,Kawaguchi, Shin-Ichi,Ogawa, Akiya
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supporting information
p. 10385 - 10388
(2015/06/25)
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- Copper-catalyzed synthesis of aromatic carboxylic acids from arylboronic acids and acetyl acetate
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A simple and efficient copper-catalyzed method for the synthesis of aromatic carboxylic acids in moderate to high yields with great functional-group compatibility in the substrates has been developed. The new method uses readily available arylboronic acids and acetyl acetate as the starting materials and inexpensive CuI as the catalyst.
- Zheng, Rui,Zhou, Qizhong,Gu, Haining,Jiang, Huajiang,Wu, Jiashou,Jin, Zhengneng,Han, Deman,Dai, Guoliang,Chen, Rener
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supporting information
p. 5671 - 5675
(2014/12/11)
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- Baeyer-Villiger oxidation of aromatic aldehydes catalysed by zirconium phosphates intercalated with ionic liquids
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Crystalline α-zirconium phosphate intercalated with 1-ethyl-3-methylimidazolium chloride or 1-hexyl-3-methylimidazolium chloride, and crystalline γ-zirconium phosphate intercalated with 1-ethyl-3-methylimidazolium chloride were synthesised, characterized and evaluated as selective catalysts in the Baeyer-Villiger oxidation of p-methoxybenzaldehyde, o-methoxybenzaldehyde and 2,4,6-trimethylbenzaldehyde by hydrogen peroxide, in glacial acetic acid or without solvent. The best selectivities of p-methoxyphenol (100 %), o-methoxyphenol (95 %) and 2,4,6-trimethylphenol (55 %) were achieved without solvent and are explained by the properties and structure of each catalyst.
- Rocha, Graca M.S.R.O.,Amador, Cristina M.T.
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p. 1197 - 1209
(2014/07/21)
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- An insight into the mechanism of the aerobic oxidation of aldehydes catalyzed by N-heterocyclic carbenes
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N-Heterocyclic carbene catalysis for the aerobic oxidation and esterification of aromatic aldehydes was monitored by ESI-MS (MS/MS) and the key intermediates were intercepted and characterized using the charge-tag strategy.
- Bortolini,Chiappe,Fogagnolo,Giovannini,Massi,Pomelli,Ragno
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supporting information
p. 2008 - 2011
(2014/03/21)
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- Copper-catalyzed carboxylation of aryl iodides with carbon dioxide
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A method for carboxylation of aryl iodides with carbon dioxide has been developed. The reaction employs low loadings of copper iodide/N,N,N′, N′-tetramethylethylenediamine (TMEDA) or N,N′- dimethylethylenediamine (DMEDA) catalyst, 1 atm of CO2, dimethylsulfoxide (DMSO) or dimethylacetamide (DMA) solvent, and proceeds at 25-70 C. Good functional group tolerance is observed, with ester, bromide, chloride, fluoride, ether, hydroxy, amino, and ketone functionalities tolerated. Additionally, hindered aryl iodides such as iodomesitylene can also be carboxylated
- Tran-Vu, Hung,Daugulis, Olafs
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p. 2417 - 2420
(2013/10/22)
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- Steric effect of substituents in haloarenes on the rate of cross-coupling reactions
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The relative reactivity of ortho- and para-methyl-substituted iodoarenes in the Sonogashira reaction and palladium-catalyzed methoxycarbonylation, as well as of similarly substituted bromoarenes in the Suzuki reactions and cobalt-catalyzed methoxycarbonylation, was studied. Introduction of a methyl group into the para position of aryl halide slows down the cross-coupling. o-Methylhaloarenes are less reactive in palladiumcatalyzed reactions as compared to both unsubstituted haloarene and para-substituted analog. The presence of a methyl group in the ortho position with respect to the reaction center accelerates cobalt-catalyzed methoxycarbonylation.
- Khaibulova, T. Sh.,Boyarskaya,Boyarskii
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p. 360 - 365
(2013/07/26)
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- Aerobic oxidation of aldehydes by visible light photocatalysis
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An efficient and environmentally benign method for the oxidation of aldehydes to carboxylic acids has been developed. Singlet oxygen, generated by visible light in the presence of a Ru or Ir photocatalyst, reacted with aldehydes to give the corresponding carboxylic acids in excellent yields. The reaction is highly chemo-selective, in which only an aldehyde moiety is reactive even in the presence of other photo-oxidation active sites. This method is an example of an ideal green chemical reaction in the sense that molecular oxygen and visible light are key sources for the transformation.
- Iqbal, Naeem,Choi, Sungkyu,You, Youngmin,Cho, Eun Jin
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supporting information
p. 6222 - 6225
(2013/10/22)
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- Method for estimating SN1 rate constants: Solvolytic reactivity of benzoates
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Nucleofugalities of pentafluorobenzoate (PFB) and 2,4,6-trifluorobenzoate (TFB) leaving groups have been derived from the solvolysis rate constants of X,Y-substituted benzhydryl PFBs and TFBs measured in a series of aqueous solvents, by applying the LFER equation: log k = sf(Ef + Nf). The heterolysis rate constants of dianisylmethyl PFB and TFB, and those determined for 10 more dianisylmethyl benzoates in aqueous ethanol, constitute a set of reference benzoates whose experimental ΔG ? have been correlated with the ΔH? (calculated by PCM quantum-chemical method) of the model epoxy ring formation. Because of the excellent correlation (r = 0.997), the method for calculating the nucleofugalities of substituted benzoate LGs have been established, ultimately providing a method for determination of the SN1 reactivity for any benzoate in a given solvent. Using the ΔG? vs ΔH? correlation, and taking sf based on similarity, the nucleofugality parameters for about 70 benzoates have been determined in 90%, 80%, and 70% aqueous ethanol. The calculated intrinsic barriers for substituted benzoate leaving groups show that substrates producing more stabilized LGs proceed over lower intrinsic barriers. Substituents on the phenyl ring affect the solvolysis rate of benzhydryl benzoates by both field and inductive effects.
- Matic, Mirela,Denegri, Bernard,Kronja, Olga
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supporting information
p. 8986 - 8998,13
(2012/12/12)
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- Irreversible catalytic ester hydrolysis of allyl esters to give acids and aldehydes by homogeneous ruthenium and ruthenium/palladium dual catalyst systems
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An irreversible hydrolysis reaction of allyl esters (1) into carboxylic acids (2) and propanal (3) was achieved with a ruthenium/palladium (Ru/Pd) dual catalyst system. The optimized catalysts consists of a 1:1:1 mixture of (cyclopentadienyl)tris(acetonitrile)ruthenium hexafluorophosphate {[RuCp(MeCN)3] PF6}, bis(acetonitrile)palladium dichloride [PdCl2(MeCN)2] and 1,6-bis(diphenylphosphanyl)hexane (DPPHex). The reaction proceeds via isomerization of allyl esters to 1-propenyl esters and hydrolysis of them to give 2 and 3. The first isomerization step was virtually catalyzed by the Ru components and the second hydrolysis step was mainly catalyzed by the Pd components. The optimized bidentate phosphine (DPPHex) which has long alkylene chain effectively generates two vacant sites on the Ru centers by bridging coordination. When a chelating bidentate phosphine such as DPPE was employed, only one vacant site remained on the Ru center and resulted in a low activity. This chelating Ru complex of DPPE formed even in the presence of 2 equivalents of Ru or additional 1 equivalent of Pd. These differences in coordination behaviour between DPPHex and 1,2- bis(diphenylphosphanyl)ethane (DPPE) cause the differences of the catalytic activity in the first step. The phosphine coordination to Pd center slightly decreases the activity of second hydrolysis step but which was compensated by the increasing of the stability of Pd. On the whole, the optimized Ru/Pd dual catalyst system exhibited good performances on the irreversible hydrolysis of allyl esters.
- Nakamura, Asami,Hamasaki, Akiyuki,Goto, Sachihiko,Utsunomiya, Masaru,Tokunaga, Makoto
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supporting information; experimental part
p. 973 - 984
(2011/06/19)
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- The Continuous-Flow Synthesis of Carboxylic Acids using CO2 in a Tube-In-Tube Gas Permeable Membrane Reactor
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Keep it simple: A gas-liquid flow reactor has been developed based on a gas permeable tube-in-tube configuration which effectively delivers gas to a liquid substrate stream in a safe, continuous fashion. A series of carboxylic acids were prepared from the reaction of CO2 with a range of Grignard reagents (see picture).
- Polyzos, Anastasios,O'Brien, Matthew,Petersen, Trine P.,Baxendale, Ian R.,Ley, Steven V.
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supporting information; experimental part
p. 1190 - 1193
(2011/04/18)
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- PEG1000-DAIL/toluene temperature-dependent biphasic system that regulate homogeneously catalyzed oxidation of primary alcohols to carboxylic acids
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An efficient and convenient procedure for the hydrogen peroxide oxidation of primary alcohols to the carboxylic acids in aqueous media in regulated temperature-dependant; recyclable phase-separation catalytic system comprised of the PEG1000-based dicationic acidic ionic liquid and toluene under homogeneous conditions in good to excellent yield is reported.
- Hu, Yu Lin,Ma, Xiao Yun,Ge, Qiang,Lu, Ming
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experimental part
p. 927 - 930
(2011/09/15)
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- Direct carboxylation of arenes and halobenzenes with CO2 by the combined use of AlBr3 and R3SiCl
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The Lewis acid-mediated direct carboxylation of aromatic compounds with CO2 is efficiently promoted by the addition of silyl chlorides bearing three alkyl and/or aryl substituents in total on the silicon atom. Thus, toluene, xylenes, mesitylene, and some other alkylbenzenes are treated with a 1:1 mixture of AlBr3 and Ph3SiCl in neat substrates under CO2 pressure (3.0 MPa) at room temperature, to give the corresponding carboxylic acids in 60-97% yields, based on AlBr3. Polycyclic arenes, including naphthalene, phenanthrene, and biphenyl, are regioselectively carboxylated in 91-98% yields with the aid of 1 molar equiv of AlBr3 and Ph3SiCl in an appropriate solvent, chosen from benzene, chlorobenzene, and fluorobenzene. These solvents, as well as bromobenzene, resist carboxylation; however, they are also carboxylated in moderate yields when treated with a 1:5 mixture of AlBr3 and iPrSiCl at elevated temperatures. The FT-IR spectrum of a mixture prepared by exposing a suspension of AlBr3 and Ph3SiCl in cyclohexane to CO 2 exhibits an absorption band around 1650 cm-1, assigned to the C=O stretching vibration of a species consisting of CO2, AlBr3, and Ph3SiCl, which suggests that the silyl chlorides activate CO2 in cooperation with AlBr3. 1H NMR analysis of unworked-up reaction mixtures reveals that the products merge as aluminum carboxylates. The mass balance concerning silicon indicates that the silyl chlorides are recycled during the reaction sequence. On the basis of these observations, a feasible mechanism is proposed for the present carboxylation.
- Nemoto, Koji,Yoshida, Hiroki,Egusa, Naoki,Morohashi, Naoya,Hattori, Tetsutaro
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experimental part
p. 7855 - 7862
(2011/02/21)
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- INHIBITORS OF STEAROYL-COA DESATURASE
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Provided herein are compounds of the formula (I): as well as pharmaceutically acceptable salts thereof, wherein the substituents are as those disclosed in the specification. These compounds, and the pharmaceutical compositions containing them, are useful for the treatment of diseases such as, for example, obesity.
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- Selective oxidation of acetophenones bearing various functional groups to benzoic acid derivatives with molecular oxygen
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Acetophenones substituted by alkyl, alkoxy, acetoxy, and halogen groups were selectively oxidized with molecular oxygen to the corresponding benzoic acids by using the N,N',N"-trihydroxyisocyanuric acid (THICA)/cobalt(II) acetate [Co(OAc)2] and THICA/Co(OAc)2/manganese(II) acetate.
- Nakamura, Ryota,Obora, Yasushi,Ishii, Yasutaka
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experimental part
p. 1677 - 1684
(2011/02/25)
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- Nucleophilic cleavage of lactones and esters with zinc selenolates prepared from diselenides in the presence of Zn/AlCl3
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The utility of zinc selenolates for effecting nucleophilic cleavage of simple lactones and esters has been investigated. When zinc selenolate generated via Zn/AlCl3-promoted cleavage of diselenides was reacted with simple lactones and esters, efficient nucleophilic alkyl-oxygen bond cleavage proceeded generating the corresponding carboxylic acids in moderate to excellent yields.
- Nazari, Mohammad,Movassagh, Barahman
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scheme or table
p. 438 - 441
(2009/05/27)
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- Oxoammonium salt/NaClO2: An expedient, catalytic system for one-pot oxidation of primary alcohols to carboxylic acids with broad substrate applicability
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A facile, green, one-pot oxidation of primary alcohols to carboxylic acids with broad substrate applicability has been developed by employing an expedient catalytic system consisting of 1-Me-AZADO+X-/NaClO 2. The Royal Society of Chemistry.
- Shibuya, Masatoshi,Sato, Takahisa,Tomizawa, Masaki,Iwabuchi, Yoshiharu
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supporting information; experimental part
p. 1739 - 1741
(2009/08/08)
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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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- Carboxylation of organoboronic esters catalyzed by N-heterocyclic carbene copper(I) complexes
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Copper complexes with a CO2 fixation: Copper(I) complexes serve as excellent catalysts for the carboxylation of aryl- and alkenylboronic esters with CO2, affording a variety of functionalized carboxylic acid derivatives (see scheme). Important active intermediates such as the copper(I) aryl and carboxylate complexes, [(IPr)CuR] and [(IPr)CuOCOR] (R = 4-MeOC 6H4, IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2- ylidene), are isolated and structurally characterized. (Chemical Equation Presented).
- Ohishi, Takeshi,Nishiura, Masayoshi,Hou, Zhaomin
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supporting information; experimental part
p. 5792 - 5795
(2009/03/11)
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- Electrosynthesis of arylalkanoic acids by oxidation of the corresponding arylalkanols at the Ni anode in aqueous alkali
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The electrochemical synthesis of a series of aryl(aryloxy)alkanoic acids was carried out by the electrocatalytic oxidation of the corresponding alcohols with the general formula RCH2CH2OH (R = Ar, CH 2Ph, OPh) in an undivided cell at the NiOOH electrode in aqueous alkali. The efficiency of the process depends on the structure of the starting alcohols, particularly, on the donor-acceptor properties of the substituent R. These properties determine the possibility of the primarily formed RCH 2COO- anion to be oxidized forming by-products. The yield of the target acids upon the oxidation of 2-(2-hydroxyethyl)pyridine, 2-phenylethanol, 3-phenylpronan-1-ol, and 2-phenoxyethanol was 15, 53, 75, and 93%, respectively, based on the reacted alcohol.
- Lyalin,Petrosyan
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p. 499 - 503
(2008/04/05)
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- Beneficial effect of TMSCl in the Lewis acid-mediated carboxylation of aromatic compounds with carbon dioxide
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The Lewis acid-mediated carboxylation of aromatic compounds with CO 2 is significantly promoted by the addition of a large excess of chlorotrimethylsilane (TMSCl) to give arylcarboxylic acids in good to excellent yields. Copyright
- Nemoto, Koji,Yoshida, Hiroki,Suzuki, Yutaka,Morohashi, Naoya,Hattori, Tetsutaro
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p. 820 - 821
(2007/10/03)
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