- Direct Acetoxylation of Arenes
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Acetoxylation of arenes is an important reaction and an unmet need in chemistry. We report a metal-free, direct acetoxylation reaction using sodium nitrate under an anhydrous environment of trifluoroacetic acid, acetic acid, and acetic anhydride. Arenes (31 examples), with oxidation potentials (Eox, in V vs SCE) lower than benzene (2.48 V), were acetoxylated with good yields and regioselectivity. A stepwise, single electron-transfer mechanism is proposed.
- Hong Nguyen, Thi Anh,Hou, Duen-Ren
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supporting information
p. 8127 - 8131
(2021/08/23)
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- One-pot process for preparing acetic acid -2, 5 -dimethylphenyl ester and 2,5 -dimethylnitrobenzene (by machine translation)
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The method comprises the following steps of: adding acetic anhydride in a single-mouth flask; adding additional p-xylene; adding the reaction solution obtained in Step III to a separatory funnel; stirring the reaction; cooling to room temperature; and quenching the reaction solution obtained in the step three steps: adding deionized water, stirring the reaction and cooling to room temperature; and quenching the reaction solution in step three steps: adding deionized water, stirring the reaction and cooling to room temperature; and thirdly, distilling the reaction solution obtained in the step three steps into dichloromethane to volatilize to obtain a product, namely acetic acid -2 -2, 5 - 5 -dimethylphenyl ester 2,5 - and 2,5 -dimethylnitrobenzene. To the method, nitrate is used as an oxidant and a nitrate agent, the price is low,2-dimethylnitrobenzene can be obtained while the acetic acid 5 - and 2,5 -dimethylphenyl ester are obtained, two products can be obtained through one-step reaction, and the utilization rate of the raw material is improved. (by machine translation)
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Paragraph 0021-0041; 0046
(2020/06/16)
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- Reusable and efficient polyvinylpolypyrrolidone-supported triflic acid catalyst for acylation of alcohols, phenols, amines, and thiols under solvent-free conditions
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Abstract: A triflic acid-functionalized polyvinylpolypyrrolidone was prepared and fully characterized by FT-IR, TGA, and SEM. This super acidic solid catalyst shows high catalytic activity for selective acylation of alcohols, phenols, amines, and thiols with anhydrides under solvent-free conditions at room temperature. In addition, this method features an easy to handle solid super acid catalyst and an operationally simple procedure, affording the desired acylated products in excellent yields. Graphical abstract: [Figure not available: see fulltext.].
- Tajbakhsh, Mahgol,Tajbakhsh, Mahmoud,Khaksar, Samad,Gazvini, Helia Janatian,Heidary, Marzieh
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p. 1117 - 1122
(2017/05/10)
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- TETRAZOLINONE COMPOUND AND APPLICATIONS THEREOF
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Disclosed is a tetrazolinone compound having a high pest control effect and represented by the formula (1): wherein R1, R2, R3, and R11 each represent a halogen atom, a C1-C6 alkyl group, or the like; R4 and R5 each represent a hydrogen atom, a halogen atom, a C1-C3 alkyl group, or the like; R6 represents a C1-C3 alkyl group which may have a halogen atom(s) or the like; R7, R8, and R9 each represent a hydrogen atom, a halogen atom, or the like; R10 represents a C1-C3 alkyl group or the like; R12 represents a C1-C6 alkyl group, a C3-C6 cycloalkyl group, or the like, and R13 represents a C1-C6 alkyl group, a C2-C6 alkenyl group, or the like.
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Paragraph 0863
(2015/11/24)
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- Palladium-catalyzed annulation of 2,2′-diiodobiphenyls with alkynes: Synthesis and applications of phenanthrenes
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A range of phenanthrene derivatives were efficiently synthesized by the palladium-catalyzed annulation of 2,2′-diiodobiphenyls with alkynes. The scope, limitations and regioselectivity of the reaction were investigated. The described method was adopted to synthesize 9,10-dialkylphenanthrenes, sterically overcrowded 4,5-disubstituted phenanthrenes and phenanthrene-based alkaloids. Reactions of highly methoxy-substituted biphenyls with 2-(2-propynyl)pyrrolidine and 2-(2-propynyl)piperidine gave 2-(9-phenanthylmethyl)pyrrolidines and 2-(9-phenanthylmethyl)piperidines, respectively. The products were transformed to phenanthroindolizidine and phenanthroquinolizidine alkaloids by the Pictet-Spengler reaction.
- Lin, Yu-De,Cho, Chun-Lung,Ko, Chih-Wei,Pulte, Anna,Wu, Yao-Ting
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p. 9979 - 9988
(2013/01/15)
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- Gold-catalyzed oxidative acyloxylation of arenes
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A variety of nonactivated hindered aromatic rings are acyloxylated (22 examples, up to 83% yield) in the presence of PPh3AuCl as the catalyst and di(acetoxy)iodobenzene as the oxidant. The reaction proceeds at 110 °C in an acid media and allows the formation of both hindered acetoxy and acyloxy derivatives. This methodology nicely complements the Pd-catalyzed arene acyloxylation reaction, which is not operating on hindered substrates and allows the Au-catalyzed unprecedented acyloxylation reaction of arenes, implying various carboxylic acids.
- Pradal, Alexandre,Toullec, Patrick Y.,Michelet, Veronique
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supporting information; scheme or table
p. 6086 - 6089
(2011/12/22)
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- Gold(III)-catalyzed direct acetoxylation of arenes with iodobenzene diacetate
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AuCl3-catalyzed direct acetoxylation of electron-rich aromatic compounds has been achieved with iodobenzene diacetate as the acetoxylation reagent.
- Qiu, Di,Zheng, Zhitong,Mo, Fanyang,Xiao, Qing,Tian, Yu,Zhang, Yan,Wang, Jianbo
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supporting information; experimental part
p. 4988 - 4991
(2011/11/13)
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- Iodonium Cyclophanes for SECURE Arene Functionalization
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This disclosure relates to compounds, reagents, and methods useful in the synthesis of aryl fluorides, for example, in the preparation of 18F labeled radiotracers. For example, this disclosure provides universal “locked” aryl substituents that result in StereoElectronic Control of Unidirectional Reductive Elimination (SECURE) from diaryliodonium salts. The reagents and methods provided herein may be used to access a broad range of compounds, including aromatic compounds, heteroaromatic compounds, amino acids, nucleotides, and synthetic compounds.
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Page/Page column 26
(2011/08/08)
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- Regiospecific reductive elimination from diaryliodonium salts
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(Figure Presented) Out-of-plane steric bulk furnished by a cyclophane substituent on iodine(III) strongly destabilizes the transition state in the reductive elimination from diaryliodonium salts and leads to regiochemical control (dubbed SECURE), as is demonstrated by computational and experimental studies. This approach should be general for high-valent maingroup and transition metal ions. X=N3, OAc, PhO, CF3CH2O, SCN, PhS.
- Wang, Bijia,Graskemper, Joseph W.,Qin, Linlin,DiMagno, Stephen G.
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supporting information; experimental part
p. 4079 - 4083
(2010/08/07)
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- Ruthenium(III) chloride catalyzed acylation of alcohols, phenols, and thiols in room temperature Ionic liquids
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Ruthenium(III) chloride-catalyzed acylation of a variety of alcohols, phenols, and thiols was achieved in high yields under mild conditions (room temperature) in the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]). The ionic liquid and ruthenium catalyst can be recycled at least 10 times. Our system not only solves the basic problem of ruthenium catalyst reuse, but also avoids the use of volatile acetonitrile as solvent.
- Xi, Zhiwen,Hao, Wenyan,Wang, Pingping,Cai, Mingzhong
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experimental part
p. 3528 - 3537
(2009/12/24)
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- Improved alkylation and product stability in phosphotriester formation through quinone methide reactions with dialkyl phosphates
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Investigating reactions of functionalized p-quinone methides continues to advance our design of a reagent being developed for controlled, in situ modification of DNA via phosphodiester alkylation. Previously reported investigations of p-quinone methides derived from catechols allowed for trapping of isolable trialkyl phosphates for characterization and mechanistic information. However, lactone formation with these derivatives required long reaction times, resulting in an unfavorable mixture of trialkyl phosphate and hydrolysis products. To enhance the rate and efficacy of trialkyl phosphate formation and trapping, a phenol derived p-quinone methide has been designed to enforce a conformation favoring lactonization of the dialkyl phosphate alkylated intermediate. The relative rates of phosphodiester alkylation and subsequent trapping of the phosphotriester adduct have been examined by UV and 1H NMR analysis for p-quinone methide precursor 1 and the corresponding control, 1′. The incorporation of a methyl group at the meta-position of 1 (relative to 1′) significantly improves the rate of lactionization to provide a much higher yield of the desired product, lactonized phosphotriester 5. The control reaction with 1′ afforded only a minor amount of the corresponding lactonized trialkyl phosphate 5′.
- Bakke, Brian A.,McIntosh, Matthias C.,Turnbull, Kenneth D.
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p. 4338 - 4345
(2007/10/03)
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- Catalytic acetylation of alcohols and phenols with potassium dodecatungstocobaltate trihydrate
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Alcohols and phenols are converted to esters in a mild, clean, and efficient reaction with acetic anhydride in the presence of a catalytic amount of potassium dodecatungstocobaltate trihydrate (K5CoW12O40· 3H2O).
- Habibi, Mohammad H.,Tangestaninejad, Shahram,Mirkhani, Valiollah,Yadollahi, Bahram
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p. 323 - 327
(2007/10/03)
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- Cobalt polyoxometalate, CoW12O405- as a new reusable catalyst for the direct, fast, and efficient acetylation of alcohols and phenols under solventless conditions
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Alcohols and phenols were efficiently acetylated with acetic anhydride without solvent in the presence of 0.01 molar equiv. of cobalt polyoxometalate (CoW12O405-).
- Habibi,Tangestaninejad,Mirkhani,Yadollahi
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p. 863 - 867
(2007/10/03)
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- Process for generating electrophiles from anions by reaction with electrophilic fluorinating agent
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A process includes substituting a substituent on a substrate. The process includes reacting a salt of an anionic form of the substituent with an electrophilic fluorination agent to provide an electrophile containing a cationic form of the substituent. The electrophile is then electrophilically substituted on the substrate. In some aspects of the process, the substrate can be an aromatic or a non-aromatic. The process can be used for a variety of reactions having electrophilic mechanisms, including halogenation, thiocyanation and nitration.
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- REACTIVITY OF 3,6-DIMETHOXY-3,6-DIMETHYLCYCLOHEXA-1,4-DIENE: NUCLEAR VERSUS BENZYLIC NUCLEOPHILIC SUBSTITUTION
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The treatment of cis/trans-3,6-dimethoxy-3,6-dimethylcyclohexa-1,4-diene (ca. 1/1 mixture; easily prepared electrochemically in multigram scale from p-xylene) under acidic conditions (acetic, trifluoroacetic, sulfuric, or a Lewis acid) yields almost exclusively 2-methoxy-1,4-dimethylbenzene 4, through a trasposition reaction.The use of aqueous hydrochloric or hydrofluoric acid gives 2,5-dimethylphenol 12, and with hydrogen chloride a mixture of 2- and α-chloro-p-xylene (13, 14) is isolated.Different oxygen-, nitrogen-, and sulfur-containing nucleophiles (alcohols,thiols, or hydrazoic acid) react with 3 under acid catalysis giving the corresponding products resulting from a nuclear or/ and benzylic substitution on p-xylene (15 - 20).The reaction of compound 3 with organolithium reagents affords exclusively benzylic products 21 in a regiospecific manner.In all cases the mixtures of isomers are separated by column chromatography.The lithiation of compound 3 with lithium powder or lithium naphthalenide fails, giving p-xylene.A probable mechanism is proposed for the studied reactions.
- Alonso, Francisco,Barba, Isidoro,Yus, Miguel
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p. 2069 - 2080
(2007/10/02)
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- Reactions of the 1-hydroxy-1,4-dimethylcyclohexadienyl cation, an intermediate in the solvolysis of 1,4-dimethyl-4-nitrocyclohexa-2,5-dien-1-ol
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Solvolysis of 1,4-dimethyl-4-nitrocyclohexa-2,5-dien-1-ol in mixed aqueous organic solvents gives the diastereomers of 1,4-dimethylcyclohexa-2,5-dien-1,4-diol, 1,4-dimethylcyclohexa-3,5-diene-1,2-diol, 2-nitro-p-xylene, 2,4-dimethylphenol (all derived from the title cation, itself formed by ionization of the nitro group as nitrite), and 2,5-dimethylphenol.In aqueous methanol the diastereomers of 4-methoxy-1,4-dimethylcyclohexa-2,5-dienol are also obtained.Significant yields of 2,5-dimethylphenol are only obtained on the acid-catalyzed further reaction of the dienediol (or the methoxydienol) and involve the intermediate formation of 1,4-dimethylcyclohexa-3,5-diene-1,2-diol.In the absence of added base the acid released in the solvolysis catalyses this reaction and leads to the aromatization of the dienes.
- Fischer, Alfred,Henderson, George N.,Smyth, Trevor A.
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p. 1093 - 1101
(2007/10/02)
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- OXYGENATION OF AROMATIC AND ALIPHATIC HYDROCARBONS BY A NEW REAGENT SYSTEM, Fe(CH3CN)6(2+)-H2O2-Ac2O: AN EFFECTIVE MODEL REAGENT FOR MONO-OXYGENASE
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Reactions of aromatic and aliphatic hydrocarbons with a new system, Fe(CH3CN)6(2+) - H2O2 - Ac2O in CH3CN, gave oxygenation products with fairly high reaction efficiency ( Tables I and II )compared to known to reagent systems used as enzyme models for mono-oxygenases.Investigations of the mechanism of these reactions indicated the involvement of either complex C.FeIV(OH)(OAc)(2+), or complex D, FeIV(OAc)(2+), dependig on the organic substrate.Keywords-oxygenation; aromatic hydrocarbon; aliphatic hydrocarbon; hexakisacetonitrile iron(II) perchlorate; hydrogen peroxide; enzyme model; mono-oxygenase
- Kotani, Eiichi,Kobayashi. Shigeki,Ishii, Yoko,Tobinaga, Seisho
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p. 4671 - 4679
(2007/10/02)
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- Ipso Nitration. Solvolytic Behavior of 1,4-Dimethyl-4-nitrohexadienyl Acetate and 1,4-Dimethyl-4-nitrocyclohexadienol
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The solvolytic rearomatizations of the E and Z isomers of 1,4-dimethyl-4-nitrocyclohexadienyl acetate (1) have been examined in aqueous ethanol and in sulfuric acid solutions.Solvolysis of 1 in aqueous ethanol involves the elimination of nitrous acid and the migration of the acetoxyl group to yield 2,5-dimethylphenyl acetate.The kinetic behavior of this solvolytic reaction parallels that of the secondary adduct 4-nitro-3,4,5-trimethylcyclohexadienyl acetate (2).No kinetic isotope effects were detected when 1,4-dimethyl-4-nitrocyclohexadienyl-2,3,5,6-d4 acetate (1-d4) or 1,4-dimethyl-4-nitrocyclohexadienyl-Me-d6 (1-d6) were used as substrates.The collected data suggest a rate-limiting loss of nitrile ion from 1 followed by migration of the acetoxyl group and proton loss.The behavior of Z and E isomers of 1,4-dimethyl-4-nitrocyclohexadienol (3) in aqueous ethanol differs from that of 1 in several ways.The major product of solvolysis is 2,4-dimethylphenol.The rates of solvolysis of the stereoisomers of 3 do not differ appreciably one from another, and the spectral yield is only 30-40percent of that anticipated.These differences are taken to reflect a rate-limiting migration in the solvolysis of 3 rather than a rate-limiting loss of nitrate ion.Solvolysis of 1 in greater than 77percent sulfuric acid gives 1,4-dimethyl-2-nitrobenzene in quantitative yield.The yield of nitro aromatic falls off smoothly as the acid concentration is lowered toward 50percent.Within the 70-50percent acid range, the yield of side-chain substitution products appears to increase, hold roughly constant, and then decrease.Larger yields of nitro aromatic and smaller yields of side-chain substitution product are found when 1-d6 is used as a reactant.The solvolyses in strong acids are discussed in terms of re-formation of the ipso ion and subsequent partitioning.
- Geppert, J. T.,Johnson, M. W.,Myhre, P. C.,Woods, S. P.
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p. 2057 - 2062
(2007/10/02)
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- Studies on Electrolytic Substitution Reactions. XVII. Selective Nuclear Acetoxylation of Alkylaromatic Compounds
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Anodic nuclear monoacetoxylation of alkylaromatics (p-xylene, isodurene, mesitylene, durene) can be achieved with high selectivity with respect to the side-chain acetate by carrying out the electrolysis in the presence of Pd on carbon in a nondevided cell.This arrangement utilizes cathodically generated hydrogen to effect cleavage of the benzylic acetate as it is formed, thus continuously regenerating the substrate.The nuclear acetate which is resistant toward hydrogenolysis accumulates in the reaction moxture.
- Eberson, Lennart,Oberrauch, Ermanno
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p. 193 - 196
(2007/10/02)
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