- 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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- Preparation method of high-selectivity 5-bromo-2-chlorobenzoic acid
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The invention provides a novel method for preparing 5-bromine-2-chlorobenzoic acid with high selectivity, and particularly relates to a method for preparing 5-bromine-2-chlorobenzoic acid with high selectivity by taking dibrominated amino silica gel as a brominating reagent, iron trifluoromethanesulfonate as a catalyst and halogenated hydrocarbon as a solvent. According to the novel method, dibrominated amino silica gel can be recycled, wherein the 6-time recovery rate reaches 98%; and the method is environment-friendly in process, simple and convenient to operate, low in EHS risk, high in product yield (more than or equal to 95%) and good in quality (more than or equal to 99.8%), is a process suitable for industrial production, greatly reduces the production cost of 5-bromo-2-chlorobenzoic acid, and remarkably reduces environmental pollution and resource consumption in the production process.
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Paragraph 0043-0057; 0060-0068
(2021/06/22)
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- Preparation method 5 - bromo -2 -chlorobenzoic acid
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The invention provides a preparation method of 5 -bromo -2 -chlorobenzoic acid, which comprises (1) contacting 2 - chlorobenzonitrile with a bromination reagent for bromination reaction to obtain 5 - bromo -2 - chlorobenzonitrile. (2) Hydrolysis of 5 - bromo -2 - chlorobenzonitrile in the presence of a base to give 5 - bromo -2 -chlorobenzoate. The 5 - bromo -2 -chlorobenzoate is then contacted with a protic acid to give 5 - bromo -2 -chlorobenzoic acid. The preparation method has the advantages of simple process, high safety, cheap and accessible raw materials, low cost and 5 - bromo -2 - chlorobenzoic acid yield, high purity and the like.
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Paragraph 0040-0041; 0044-0045; 0049; 0052-0054; 0057-0058
(2021/09/01)
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- Preparation method of 5-bromo-2-chlorobenzoic acid
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The invention relates to a preparation method of 5-bromo-2-chlorobenzoic acid. The preparation method comprises the following steps: taking 2-chlorobenzoic acid as an initial reactant, sequentially carrying out chlorination, acylation and cyclization reactions to obtain a protective group o-chlorobenzoic acid (a compound represented by formula III), and sequentially carrying out bromination and hydrolysis to obtain 5-bromo-2-chlorobenzoic acid. The reaction conditions are mild, and the safety of the preparation process is improved. The yield of the prepared product can reach 75% or above, thepurity can reach 99% or above, and the purity and yield are much higher than those of an existing preparation method. Meanwhile, the preparation method is simple in process step, the product is easy to purify, 5-bromo-2-chlorobenzoic acid can be synthesized on a large scale, and the preparation method has a good industrial development prospect.
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Paragraph 0020; 0032; 0037; 0039-0040; 0041; 0046; 0048-0049
(2020/11/26)
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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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- Preparation method of 5-bromo-2-chlorobenzoic acid
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The invention relates to a preparation method of 5-bromo-2-chlorobenzoic acid, which is characterized by comprising the following steps: reacting 2-chlorobenzotrichloride used as a raw material with abromination reagent under the catalytic action of a first catalyst to generate 2-chloro-5-bromobenzotrichloride, adding water and a hydrolysis catalyst into the 2-chloro-5-bromobenzotrichloride, andcarrying out after-treatment and purification to obtain 5-bromo-2-chlorobenzoic acid, wherein the first catalyst is prepared by compounding iron bromide, ferrous bromide, copper bromide, (ferrocene methyl) trimethyl ammonium bromide and brominated ferrocene. The invention further discloses the 5-bromine-2-chlorobenzoic acid prepared according to the preparation method of the 5-bromine-2-chlorobenzoic acid. According to the preparation method of 5-bromine-2-chlorobenzoic acid disclosed by the invention, the traditional preparation process conditions are optimized and innovated, so that the product purity, the reaction conversion rate and the production efficiency are effectively improved, the preparation cost is low, the environmental pressure is low, the synthesis route is short, the operation is simple and feasible, the emission of three wastes is reduced, and the reaction yield is high.
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Paragraph 0029-0051
(2020/09/16)
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- Preparation method of 5-bromo-2-chlorobenzoic acid
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The invention relates to the technical field of preparation of 5-bromo-2-chlorobenzoic acid, and in particular relates to a preparation method of the 5-bromo-2-chlorobenzoic acid. The preparation method of the 5-bromo-2-chlorobenzoic acid provided by the invention comprises the following steps: mixing 2-chlorobenzoic acid, bromine, a catalyst and an organic solvent, and performing a bromination reaction to obtain the 5-bromo-2-chlorobenzoic acid. The preparation method provided by the invention has short steps, mild reaction conditions, low costs, a high yield, and high purity of the product;and at the same time, according to the description of embodiments, the purity by HPLC of the 5-bromo-2-chlorobenzoic acid prepared by using the preparation method is >=99.5%, and the molar yield is >=80.9%.
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Paragraph 0048-0064
(2020/01/03)
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- Preparation method of high-selectivity 5-bromo-2-chlorobenzoic acid
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The invention discloses a preparation method of 5-bromo-2-chlorobenzoic acid and belongs to the technical field of organic synthesis. According to the preparation method, 2-chlorobenzoic acid is takenas a raw material and is subjected to a mono-bromination reaction in an NBS/sulfuric acid system, 5-bromo-2-chlorobenzoic acid is prepared, and a catalyst inhibiting production of 4-bromo-2-chlorobenzoic acid is added in the reaction process. The process is simple, raw materials are cheap and easy to obtain, the cost is low, the yield is high, and the high-purity 5-bromo-2-chlorobenzoic acid product is obtained through one-time refining after the reaction; the catalyst can effectively inhibit production of impurities such as 4-bromo-2-chlorobenzoic acid and the like, and the impurity contentof the obtained product is low.
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Paragraph 0015-0019
(2019/08/20)
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- Synthesis method of 2-halo-5-bromobenzoic acid
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The invention discloses a synthesis method of 2-halo-5-bromobenzoic acid. The method comprises the following steps of under the action of sulfuric acid, carrying out a bromination reaction on o-halo-benzoic acid and NBS in an organic solvent, and after the reaction is finished, carrying out posttreatment to obtain 2-halo-5-bromobenzoic acid. The method has the advantages of being short in reactionroute, simple in operation, environmentally friendly, safe and economical and has a broad application prospect.
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Paragraph 0031-0037
(2019/10/01)
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- Preparation method of 2,5-dihalo-benzoic acid
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The invention discloses a preparation method of 2,5-dihalo-benzoic acid. The method comprises the following steps: concentrated sulfuric acid is added dropwise to a mixed solution containing sodium bromide, periodate and 2-halo-benzoic acid in presence of water and acetic acid, the mixed solution is subjected to a reaction, and 2,5-dihalo-benzoic acid is prepared. The problems of long time neededfor preparation, high reaction temperature and the like of the preparation method of 2,5-dihalo-benzoic acid in the prior art can be solved.
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Paragraph 0032-0034
(2018/05/16)
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- Carbon glucoside sodium glucose transport protein body 2 inhibitor
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The invention relates to a carbon glucoside sodium glucose transport protein body 2 inhibitor, a preparation method and an application of the inhibitor. The carbon glucoside sodium glucose transport protein body 2 inhibitor has a structure as shown in general formula (I) as shown in the specification.
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Paragraph 0038; 0091-0093
(2018/07/30)
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- Synthetic method of 5-bromo-2-chlorobenzoic acid
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The invention discloses a synthetic method of 5-bromo-2-chlorobenzoic acid. The method comprises the following steps of by taking salicylic acid as a starting material, performing bromination reactionto obtain 2-hydroxyl-5-bromo-benzoic acid, and then performing chlorination reaction to obtain the 5-bromo-2-chlorobenzoic acid, wherein a bromination system adopted by the bromination reaction is tetrabutyl ammonium bromide/oxygen/sodium metavanadate, a catalyst is aluminium tribromide, and a solvent is 1,4-dioxane; and a chlorinating agent is carbon tetrachloride, and a catalyst is molybdenum hexacarbonyl. The method provided by the invention adopts the cheap salicylic acid which is wide in source as the starting material and prepares the 5-bromo-2-chlorobenzoic acid through two-step reaction of bromination and chlorination, is novel in synthetic route, relatively low in production cost, relatively small in environmental pollution and very suitable for industrial mass production. According to the method, through the bromination reaction and the chlorination reaction, by selecting proper reagents, relatively high reaction yield and product purity can be obtained.
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Paragraph 0016; 0059-0062
(2018/07/30)
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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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- 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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- New post-treatment technology of 5-bromo-2-chlorobenzoic acid
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The invention relates to a new post-treatment technology of 5-bromo-2-chlorobenzoic acid. The technology comprises the following steps: 1, reacting 2-chlorobenzotrichloride with bromine under the action of a catalyst to prepare 2-chloro-5-bromobenzotrichloride, adding an organic acid, carrying out a heating reaction, and concentrating the obtained reaction product after the reaction ends to recover the organic acid; and 2, adding water to a concentrate obtained in step 1 to precipitate crystals, and filtering the obtained solution to obtain crude 5-bromo-2-chlorobenzoic acid. The technology solves the problem of the wastewater problem of large amounts of H2SO4, HCl, ferric chloride or ferric bromide, other high-concentration acids and salts generated in the reaction and the hidden safety trouble problem in the prior art, is safe and environmentally-friendly, and is economical and practical due to the concentrated and recovered organic acid which can be directly repeatedly used.
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Paragraph 0033; 0034; 0035; 0036; 0037; 0038; 0039-0047
(2017/10/07)
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- Synthesis method of 5-bromo-2-chloro benzoic acid
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The invention provides a synthesis method of 5-bromo-2-chloro benzoic acid.The method includes the following steps of A, making 2-chlorine benzotrichloride and bromide reagents react under the effect of a catalyst to obtain 2-chloro-5-bromine benzotrichloride, wherein bromide reagents include one or more of bromine, N-bromosuccinimide, dibromohydantoin and hydrobromic acid; B, conducting hydrolysis reaction on 2-chloro-5-bromine benzotrichloride in the step A under the acid condition to obtain 5-bromo-2-chloro benzoic acid.According to the method, 2-chlorine benzotrichloride which is low in price and easy to obtain is adopted as the raw material, operation is easy, intermediates do not need to be purified, 5-bromo-2-chloro benzoic acid is synthesized through a one-pot method, purity is high, yield is high, three-waste emission is little, and production cost is low.It is shown through experiment results that 2-chloro-5-benzoic acid obtained according to the synthesis method has yield larger than 95% and purity of 80-92%.
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Paragraph 0053; 0054
(2017/03/14)
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- A novel practical cleavage of tert-butyl esters and carbonates using fluorinated alcohols
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Thermolytic cleavage of t-butyl esters and t-butyl carbonates was accomplished using TFE (2,2,2-trifluoroethanol) or HFIP (hexafluoroisopropanol) as solvent. Thus, a practical method to cleanly convert t-butyl esters and carbonates into the corresponding carboxylic acids, decarboxylated products, or alcohols in nearly quantitative yields was developed. The product is recovered by a simple solvent evaporation. The practicality of this methodology was demonstrated on alkyl, aryl, and heteroaromatic esters.
- Choy, Jason,Jaime-Figueroa, Saul,Lara-Jaime, Teresa
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experimental part
p. 2244 - 2246
(2010/05/18)
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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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- The acidifying effects of chlorine and bromine: Little difference
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Lithium diisopropylamide deprotonates ortho- and para-bromochlorobenzene randomly at the two halogen adjacent positions. Obviously for steric reasons, the bulkier base lithium 2,2,6,6-tetramethylpiperidide favors the attack in the vicinity of the chlorine rather than the bromine atom to the extent of 2:1. At -75°C, both 2-bromo-3-chlorophenyllithium and 3-bromo-2-chlorophenyllithium isomerize to give 2-bromo-6-chlorophenyllithium. The latter species can be directly generated from 1-bromo-3-chlorobenzene.
- Mongin, Florence,Schlosser, Manfred
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p. 1559 - 1562
(2007/10/03)
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- Use of Potassium Bromate: Bromination of Halobenzenes and Halobenzoic Acids
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Syntheses of bromo compounds by the bromination of halobenzenes and halobenzoic acids using potassium bromate under acidic condition have been discussed.
- Banerjee, Amalendu,Banerjee, Gopal Chandra,Dutt, Sachchidananda,Banerjee, Santa (Mrs.),Samaddar, Haraprasad
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p. 640 - 642
(2007/10/02)
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