- 1,2-Dibutoxyethane-Promoted Oxidative Cleavage of Olefins into Carboxylic Acids Using O2 under Clean Conditions
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Herein, we report the first example of an effective and green approach for the oxidative cleavage of olefins to carboxylic acids using a 1,2-dibutoxyethane/O2 system under clean conditions. This novel oxidation system also has excellent functional-group tolerance and is applicable for large-scale synthesis. The target products were prepared in good to excellent yields by a one-pot sequential transformation without an external initiator, catalyst, and additive.
- Ou, Jinhua,Tan, Hong,He, Saiyu,Wang, Wei,Hu, Bonian,Yu, Gang,Liu, Kaijian
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p. 14974 - 14982
(2021/10/25)
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- Preparation method of 4-formylbenzoic acid
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The invention provides a preparation method of 4-formylbenzoic acid, and the method comprises the following steps: by using 4-methylbenzoyl chloride as a raw material, performing chlorinating to obtain 4-chloromethylbenzoyl chloride, performing hydrolyzing to obtain 4-chloromethyl benzoic acid, and reacting with urotropine to obtain 4-formylbenzoic acid. The method provided by the invention is simple in process, does not need special equipment and is relatively low in cost; moreover, the method provided by the invention is relatively high in product yield and purity, and large-scale industrialproduction is easy to realize. The result of the embodiment shows that the yield of each step of the preparation method of the 4-formylbenzoic acid provided by the invention is greater than or equalto 90%, and the purity of the finally obtained 4-formylbenzoic acid is greater than or equal to 99.7%.
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Paragraph 0058; 0061-0063; 0066-0067; 0070
(2020/11/23)
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- Preparation method of aminomethylbenzoic acid
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The invention belongs to the technical field of chemical synthesis, and particularly relates to a preparation method of aminomethylbenzoic acid. The method comprises the following steps: carrying outchlorination reaction on p-toluic acid and a chlorination reagent under the condition of a catalyst I to obtain an intermediate p-chloromethylbenzoic acid, and carrying out ammonolysis on the intermediate p-chloromethylbenzoic acid and ammonia water under the condition of a catalyst II to prepare aminomethylbenzoic acid. The purity of the obtained product aminomethylbenzoic acid is greater than 99.9%, the single impurity content is less than 0.1%, and the overall yield of the two-step reaction is greater than 63%. The method is short in synthetic route, free of highly toxic reagents or precious metals, low in production cost, less in environmental pollution, high in overall yield and suitable for large-scale industrial production.
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Page/Page column 0029; 0031
(2020/12/29)
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- Ferric(III) Chloride Catalyzed Halogenation Reaction of Alcohols and Carboxylic Acids Using α,α-Dichlorodiphenylmethane
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A new method for chlorination of alcohols and carboxylic acids, using α,α-dichlorodiphenylmethane as the chlorinating agent and FeCl3 as the catalyst, was developed. The method enables conversions of various alcohols and carboxylic acids to their corresponding alkyl and acyl chlorides in high yields under mild conditions. Particulary interesting is the observation that the respective alkyl bromides and iodides can be generated from alcohols when either LiBr or LiI are present in the reaction mixtures.
- Lee, Chang-Hee,Lee, Soo-Min,Min, Byul-Hana,Kim, Dong-Su,Jun, Chul-Ho
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supporting information
p. 2468 - 2471
(2018/04/25)
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- A General Catalytic Method for Highly Cost- and Atom-Efficient Nucleophilic Substitutions
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A general formamide-catalyzed protocol for the efficient transformation of alcohols into alkyl chlorides, which is promoted by substoichiometric amounts (down to 34 mol %) of inexpensive trichlorotriazine (TCT), is introduced. This is the first example of a TCT-mediated dihydroxychlorination of an OH-containing substrate (e.g., alcohols and carboxylic acids) in which all three chlorine atoms of TCT are transferred to the starting material. The consequently enhanced atom economy facilitates a significantly improved waste balance (E-factors down to 4), cost efficiency, and scalability (>50 g). Furthermore, the current procedure is distinguished by high levels of functional-group compatibility and stereoselectivity, as only weakly acidic cyanuric acid is released as exclusive byproduct. Finally, a one-pot protocol for the preparation of amines, azides, ethers, and sulfides enabled the synthesis of the drug rivastigmine with twofold SN2 inversion, which demonstrates the high practical value of the presented method.
- Huy, Peter H.,Filbrich, Isabel
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supporting information
p. 7410 - 7416
(2018/04/30)
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- Highly selective halogenation of unactivated C(sp3)-H with NaX under co-catalysis of visible light and Ag@AgX
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The direct selective halogenation of unactivated C(sp3)-H bonds into C-halogen bonds was achieved using a nano Ag/AgCl catalyst at RT under visible light or LED irradiation in the presence of an aqueous solution of NaX/HX as a halide source, in air. The halogenation of hydrocarbons provided mono-halide substituted products with 95% selectivity and yields higher than 90%, with the chlorination of toluene being 81%, far higher than the 40% conversion using dichlorine. Mechanistic studies demonstrated that the reaction is a free radical process using blue light (450-500 nm), with visible light being the most effective light source. Irradiation is proposed to cause AgCl bonding electrons to become excited and electron transfer from chloride ions induces chlorine radical formation which drives the substitution reaction. The reaction provides a potentially valuable method for the direct chlorination of saturated hydrocarbons.
- Liu, Shouxin,Zhang, Qi,Tian, Xia,Fan, Shiming,Huang, Jing,Whiting, Andrew
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p. 4729 - 4737
(2018/10/23)
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- One-Step Trimethylstannylation of Benzyl and Alkyl Halides
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Trialkylstannanes are good leaving groups that have been used for the formation of carbon-metal bonds to electrode surfaces for analyses of single-molecule conductivity. Here, we report the multistep synthesis of two amide-containing compounds that are of interest in studies of molecular rectifiers. Each molecule has two trimethylstannyl units, one linked by a methylene and the other by an ethylene group. To account for the very different reactivities of the parent halides, a new methodology for one-step trimethylstannylation was developed and optimized.
- Jiang, Jianbing,Crabtree, Robert H.,Brudvig, Gary W.
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p. 9483 - 9488
(2016/10/14)
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- Silver-catalyzed decarboxylative chlorination of aliphatic carboxylic acids
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Decarboxylative halogenation of carboxylic acids, the Hunsdiecker reaction, is one of the fundamental functional group transformations in organic chemistry. As the initial method requires the preparations of strictly anhydrous silver carboxylates, several modifications have been developed to simplify the procedures. However, these methods suffer from the use of highly toxic reagents, harsh reaction conditions, or limited scope of application. In addition, none is catalytic for aliphatic carboxylic acids. In this Article, we report the first catalytic Hunsdiecker reaction of aliphatic carboxylic acids. Thus, with the catalysis of Ag(Phen)2OTf, the reactions of carboxylic acids with t-butyl hypochlorite afforded the corresponding chlorodecarboxylation products in high yields under mild conditions. This method is not only efficient and general, but also chemoselective. Moreover, it exhibits remarkable functional group compatibility, making it of more practical value in organic synthesis. The mechanism of single electron transfer followed by chlorine atom transfer is proposed for the catalytic chlorodecarboxylation.
- Wang, Zhentao,Zhu, Lin,Yin, Feng,Su, Zhongquan,Li, Zhaodong,Li, Chaozhong
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experimental part
p. 4258 - 4263
(2012/04/10)
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- PROCESS FOR PREPARING 4-NITRO-OXY-METHYL-BENZOIC ACID
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This invention relates to a new process for preparing 4-nitro-oxy-methyl- benzoic acid, comprising the following steps: a) reaction of 4-chloromethyl-benzoic acid with silver nitrate and in the presence of an acid as a catalyst in acetonitrile at reflux temperature, followed by cooling and adding of a polar aprotic solvent; b) separation of the silver salts by filtration, followed by washout with a polar aprotic solvent; c) precipitation of the 4-nitro-oxy-methyl-benzoic acid with water from the filtrate obtained in step b); and d) drying of the 4-nitro-oxy-methyl-benzoic acid.
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Page/Page column 7-8
(2011/06/16)
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- N-Cycloalkanoyl-L-phenylalanine derivatives as VCAM/VLA-4 antagonists.
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A systematic structure-activity relationship investigation of the lead compound 1 resulted the identification of several N-[(substituted alkyl)cycloalkanoyl]-4-[((2,6-dichlorophenyl)carbonyl)amino]-L-phenylalanine derivatives as potent VCAM/VLA-4 antagonists. The data are consistent with a model of these compounds in which these alkanoylphenylalanines reside in a compact gauche (-) bioactive conformation.
- Sidduri, Achyutharao,Tilley, Jefferson W,Hull, Kenneth,Lou, Jian Ping,Kaplan, Gerry,Sheffron, Allen,Chen,Campbell, Robert,Guthrie, Robert,Huang, Tai-Nan,Huby, Nicholas,Rowan, Karen,Schwinge, Virginia,Renzetti, Louis M
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p. 2475 - 2478
(2007/10/03)
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- Kinetics of the reaction of sodium arylthiolates with nitro-carboxybenzyl halide derivatives
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The rate constants for the reactions of 4-halomethyl-3-nitrobenzoic acids, the nonnitro derivatives, and their ethyl esters with arylthiolates were measured at different temperatures. It was found that the retardation in rate constants compared to benzyl halides is due to the electrostatic repulsion between the electronegative substituents (COO- and/or NO2) in the substrates and thiolate ions Good correlations between log K2 values of the acids and carbon basicities of thiolates were found while log k2 values of the esters show good straight lines with Hammett a constants, pKa. and carbon basicities of arylthiolates.
- Hamed, Ezzat A.,El-Bardan, Ali A.,El-Mallah, Nabila M.
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p. 283 - 289
(2007/10/03)
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- Process for the preparation of esters of stilbenedicarboxylic acid
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Disclosed is a process for the preparation of 4,4'-stilbenedicarboxylate esters by a 3-step process utilizing p-toluic acid, an alkyl p-formylbenzoate and a trialkyl phosphite. The steps comprise (1) preparing p-(chloromethyl)benzoic acid by chlorinating p-toluic acid with sulfuryl chloride in the presence of a free radical initiator and chlorobenzene or dichlorobenzene; (2) contacting the p-(chloromethyl)benzoic acid of step (1) with a trialkyl phosphite to obtain a phosphonate compound; and (3) contacting the phosphonate ester compound of step (2) with an alkyl p-formylbenzoate in the presence of an alkali metal alkoxide and an inert solvent to obtain the dialkyl 4,4'-stilbenedicarboxylate.
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- Oxidation of Aromatic Compounds. II. Oxidation of Methyl Derivatives of Benzoic Acid and Acetophenone in the System HSO3F-PbO2
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Low-temperature oxidation of methyl derivatives of benzoic acid and acetophenone in the system HSO3F-PbO2 proceeds with intermediate formation of radical cations and results in replacement of hydrogen atom in methyl group or benzene ring.The reaction allows preparation of various substituted derivatives of benzyl alcohols and alkylated phthalides.
- Rudenko, A. P.,Korovina, N. S.
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p. 1084 - 1088
(2007/10/03)
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- THE ESR SPECTRA, STRUCTURE, AND REACTIVITY OF AROMATIC RADICAL-CATIONS IN SUPERACIDS
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The oxidation of aromatic compounds by lead dioxide in superacids based on fluorosulfonic acid at -75 deg C takes place by a one-electron mechanism and leads in many cases to relatively stable radical-cations.The ESR spectra, the isotropic hyperfine coupling constants, data on the reactivity of the radical-cations, and the structures of the final products from their transformations under "long-life" conditions are presented.
- Rudenko, A. P.
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p. 1946 - 1980
(2007/10/03)
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- OXIDATION BY THE SALTS OF METALS. IV. OXIDATIVE HALOGENATION OF TOLUENE AND PARA-SUBSTITUTED TOLUENES WITH ELECTRON-WITHDRAWING GROUPS PROMOTED BY CERIUM(IV) SALTS IN AQEOUS SOLUTIONS OF TRIFLUOROACETIC ACID
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The oxidation of toluene and para-substituted toluenes with electron-withdrawing groups (para-toluic acid, methyl para-toluate, and para-nitrotoluene) by ammonium cerium(IV) nitrate and ammonium cerium(IV) sulfate was investigated in aqueous solutions of trifluoroacetic acid in the presence of alkali-metal chlorides and bromides.The rate and selectivity of oxidative halogenation in the side chain and/or aromatic ring under the investigated conditions depends strongly both on the nature of the substrate and the halide ion and on the reaction conditions and the ligand environment of the cerium(IV) atom.The oxidation of nitrotoluene takes place only in the presence of the bromide-containing systems and leads to the production of 4-nitrobenzyl bromide.For the other substrates halogenation in the aromatic ring can be realized with yields close to quantitative with ammonium cerium(IV) nitrate as oxidizing agent in concentrated aqueous solutions of trifluoroacetic acid (10 vol.percent of water).It was shown that the halogenating agents in this case are mainly the products from oxidation of the halide ions by the nitronium ions formed in the strongly acidic medium from the nitrate ions contained in the ammonium cerium(IV) nitrate.Bromination of the substituted toluenes in the presence of ammonium cerium(IV) sulfate and in the ammonium cerium(IV) nitrate-alkali-metal bromide systems with more than 10 vol.percent of water takes mainly in the side chain and can be used as a method for the production of 4-substituted benzyl halides with preparative yields.The effect of the composition of the solvent and the ratio of the oxidizing agent and alkali-metal halide on the rate and selectivity of oxidative bromination was studied.Possible reaction mechanisms are discussed.
- Makhon'kov, D.I.,Cheprakov, A.V.,Rodkin, M.A.,Mil'chenko, A.Yu.,Beletskaya, I.P.
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- Water-soluble, fiber-reactive organic dyestuffs containing a β-chloro-ethylsulfonyl-methyl-benzoic acid amide group
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Novel organic, water-soluble compounds having fiber-reactive and fiber-finishing properties and containing, as a fiber-reactive group, one or two β-chloroethylsulfonylmethyl-benzoic acid amide groups. These compounds can be prepared (1) by reacting novel β-chloroethylsulfonylmethyl-benzoic acid halide compounds with an organic, water-soluble compound having fiber-finishing properties and containing one or two amino groups, or (2) analogously to known and usual procedures, from precursors containing the β-chloroethylsulfonylmethyl-benzoic acid amide grouping. The novel fiber-finishing compounds are applied to and fixed on suitable fiber materials, especially cellulose fiber material and natural or synthetic polyamide fiber materials, by methods corresponding to those which are conventional for application and fixation of fiber-reactive compounds. The above-mentioned β-chloroethylsulfonylmethyl-benzoic acid halides are synthesized by monochlorinating the methyl grouping of a toluenecarboxylic acid or an alkyl ester thereof or an acid halide thereof, converting this monochlorinated compound by reaction with 2-mercaptoethanol in aqueous solution, optionally with simultaneous hydrolysis of the carboxylic acid chloride group, to form the thioether compound, hydrolyzing the carbalkoxy grouping optionally present in this thioether compound, and then oxidizing said thioether compound by means of an oxidizing agent to form the corresponding sulfonyl compound; the β-hydroxyethylsulfonylmethyl grouping is subsequently reacted with a chlorinating agent.
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- Oxidation by the salts of metals. I. Anaerobic oxidation of p-toluic acid by the salts of transition metals in trifluoroacetic acid in the presence of alkali-metal halides
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The oxidation of p-toluic acid by the salts of metals with variable valence was investigated in trifluoroacetic acid and its aqueous solutions in the presence of alkali-metal halides (chlorides or bromides).The reaction leads to the formation of the products from oxidative halogenation in the aromatic ring and/or the side chain.The rate and direction of the reaction depend both on the nature of the oxidizing agent and the halide ion and on the ratio of the components in the p-toluic acid-Hlg--CF3CO2H-H2O system.Preferential halogenation in the ring is observed for Ce(IV) and Pb(IV) in the presence of sodium bromide and for all the oxidizing agents in the presence of potassium chloride.In the case of Co(III) and Mn(III) bromination in the presence of Br- takes place mainly in the side chain and is greatly accelerated by additions of water.Conditions were found for the production of 3-chloro- and 3-bromo-p-toluic acid and 4-carboxybenzyl bromide with preparative yields.
- Beletskaya, I. P.,Dem'yanov, P. I.,Makhon'kov, D. I.,Zel'dis, I. M.,Burenko, S. N.
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p. 583 - 591
(2007/10/02)
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