- Preparation and trapping of 3-lithium-O-lithiophenoxide
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3-Bromophenol and 3-bromothiophenol are converted into the title compounds by proton abstraction followed by halogen-metal exchange with tert-butyllithium. The resulting dianions are then trapped on carbon with various electrophiles.
- Selnick,Bourgeois,Butcher,Radzilowski
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Read Online
- Palladium(II)-catalyzed aerobic hydroalkoxylation of styrenes containing a phenol
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An intermolecular Pd-catalyzed hydroalkoxylation of styrenes that contain a phenol is presented. The reaction can be performed on terminal, disubstituted, and trisubstituted olefins in a variety of alcoholic solvents. Initial mechanistic data suggest a mechanism that involves oxidation of the alcoholic solvent to provide a Pd-hydride that inserts into an olefin. This is followed by formation of a quinone methide and subsequent addition of an alcohol to yield the hydroalkoxylated product. Copyright
- Gligorich, Keith M.,Schultz, Mitchell J.,Sigman, Matthew S.
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Read Online
- Efficient microwave-assisted Pd-catalyzed hydroxylation of aryl chlorides in the presence of carbonate
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An efficient microwave-assisted, palladium-catalyzed hydroxylation of aryl chlorides in the presence of a weak base carbonate was developed, which rapidly converts aryl and heteroaryl chlorides to phenols, and can be used when the aryl chloride is functionalized with a ketone, aldehyde, ester, nitrile, or amide.
- Yu, Chao-Wu,Chen, Grace S.,Huang, Chen-Wei,Chern, Ji-Wang
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Read Online
- Rapid, chemoselective and mild oxidation protocol for alcohols and ethers with recyclable N-chloro-N-(phenylsulfonyl)benzenesulfonamide
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Chlorine is the 20th most abundant element on the earth compared to bromine, iodine, and fluorine, a sulfonimide reagent, N-chloro-N-(phenylsulfonyl)benzenesulfonamide (NCBSI) was identified as a mild and selective oxidant. Without activation, the reagent was proved to oxidize primary and secondary alcohols as well as their symmetrical and mixed ethers to corresponding aldehydes and ketones. With recoverable PS-TEMPO catalyst, selective oxidation over chlorination of primary and secondary alcohols and their ethers with electron-donating substituents was achieved. The reagent precursor of NCBSI was recovered quantitatively and can be reused for synthesizing NCBSI.
- Badani, Purav,Chaturbhuj, Ganesh,Ganwir, Prerna,Misal, Balu,Palav, Amey
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supporting information
(2021/06/03)
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- Visible light mediated selective oxidation of alcohols and oxidative dehydrogenation of N-heterocycles using scalable and reusable La-doped NiWO4nanoparticles
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Visible light-mediated selective and efficient oxidation of various primary/secondary benzyl alcohols to aldehydes/ketones and oxidative dehydrogenation (ODH) of partially saturated heterocycles using a scalable and reusable heterogeneous photoredox catalyst in aqueous medium are described. A systematic study led to a selective synthesis of aldehydes under an argon atmosphere while the ODH of partially saturated heterocycles under an oxygen atmosphere resulted in very good to excellent yields. The methodology is atom economical and exhibits excellent tolerance towards various functional groups, and broad substrate scope. Furthermore, a one-pot procedure was developed for the sequential oxidation of benzyl alcohols and heteroaryl carbinols followed by the Pictet-Spengler cyclization and then aromatization to obtain the β-carbolines in high isolated yields. This methodology was found to be suitable for scale up and reusability. To the best of our knowledge, this is the first report on the oxidation of structurally diverse aryl carbinols and ODH of partially saturated N-heterocycles using a recyclable and heterogeneous photoredox catalyst under environmentally friendly conditions.
- Abinaya, R.,Balasubramaniam, K. K.,Baskar, B.,Divya, P.,Mani Rahulan, K.,Rahman, Abdul,Sridhar, R.,Srinath, S.
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p. 5990 - 6007
(2021/08/24)
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- Hydration of Alkynes to Ketones with an Efficient and Practical Polyoxomolybdate-based Cobalt Catalyst
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Hydration of alkynes to ketones is one of the most atom economical and universal methods for the synthesis of carbonyl compounds. However, the basic reaction usually requires organic ligand catalysts or harsh reaction conditions to insert oxygen into the C≡C bond. Here, we report an inorganic ligand supported cobalt (III) catalyst, (NH4)3[CoMo6O18(OH)6], which is supported by a central cobalt (III) mononucleus and a ring-shaped pure inorganic ligand composed of six MoVIO6 octahedrons to avoid the disadvantages of expensive and unrecyclable organic ligand catalysts or noble metal catalysts. Under mild conditions, the cobalt (III) catalyst can be used for the hydration of alkynes to ketones. The catalyst is non-toxic, green, and environment friendly. The catalyst can be recycled at least six times with high activity. According to control experiments, a reasonable mechanism is provided.
- Xie, Ya,Wang, Jingjing,Wang, Yunyun,Han, Sheng,Yu, Han
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p. 4985 - 4989
(2021/10/12)
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- Nickel-catalyzed deallylation of aryl allyl ethers with hydrosilanes
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An efficient and mild catalytic deallylation method of aryl allyl ethers is developed, with commercially available Ni(COD)2 as catalyst precursor, simple substituted bipyridine as ligand and air-stable hydrosilanes. The process is compatible with a variety of functional groups and the desired phenol products can be obtained with excellent yields and selectivity. Besides, by detection or isolation of key intermediates, mechanism studies confirm that the deallylation undergoes η3-allylnickel intermediate pathway.
- Ding, Guangni,Fan, Sijie,Wang, Jingyang,Wang, Yu,Wu, Xiaoyu,Xie, Xiaomin,Yang, Liqun,Zhang, Zhaoguo
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supporting information
(2021/09/28)
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- Iron-catalyzed domino decarboxylation-oxidation of α,β-unsaturated carboxylic acids enabled aldehyde C-H methylation
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A practical and general iron-catalyzed domino decarboxylation-oxidation of α,β-unsaturated carboxylic acids enabling aldehyde C-H methylation for the synthesis of methyl ketones has been developed. This mild, operationally simple method uses ambient air as the sole oxidant and tolerates sensitive functional groups for the late-stage functionalization of complex natural-product-derived and polyfunctionalized molecules.
- Gong, Pei-Xue,Xu, Fangning,Cheng, Lu,Gong, Xu,Zhang, Jie,Gu, Wei-Jin,Han, Wei
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supporting information
p. 5905 - 5908
(2021/06/18)
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- Efficient aerobic oxidation of ethylbenzene accelerated by cu species in hydrotalcite
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The simply prepared CuMgAl hydrotalcite (CuMgAl-LDH) has been developed as an efficient catalyst for the aerobic oxidation of ethylbenzene to acetophenone in the presence of N-Hydroxyphthalimide (NHPI). Various alkyl arenes could be tolerated under the selected reaction conditions. The kinetic study showed that the oxidation of ethylbenzene is a first-order reaction over CuMgAl-LDH. The mechanism study indicated that CuMgAl-LDH could accelerate not only the conversion of ethylbenzene, but also the transformation of the alcohol intermediate to ketone. The positive effect of surface basicity of the catalyst on the reaction has been observed in the aerobic oxidation of the ethylbenzene.
- Dai, Xuan,Jiang, Ou,Li, Xingyan,Peng, Xinhua,Tang, Shuangling,Zheng, Xuegen
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- Iron-catalyzed arene C-H hydroxylation
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The sustainable, undirected, and selective catalytic hydroxylation of arenes remains an ongoing research challenge because of the relative inertness of aryl carbon-hydrogen bonds, the higher reactivity of the phenolic products leading to over-oxidized by-products, and the frequently insufficient regioselectivity. We report that iron coordinated by a bioinspired L-cystine-derived ligand can catalyze undirected arene carbon-hydrogen hydroxylation with hydrogen peroxide as the terminal oxidant. The reaction is distinguished by its broad substrate scope, excellent selectivity, and good yields, and it showcases compatibility with oxidation-sensitive functional groups, such as alcohols, polyphenols, aldehydes, and even a boronic acid. This method is well suited for the synthesis of polyphenols through multiple carbon-hydrogen hydroxylations, as well as the late-stage functionalization of natural products and drug molecules.
- Cheng, Lu,Wang, Huihui,Cai, Hengrui,Zhang, Jie,Gong, Xu,Han, Wei
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- Aryl phenol compound as well as synthesis method and application thereof
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The invention discloses a synthesis method of an aryl phenol compound shown as a formula (3). All systems are carried out in an air or nitrogen atmosphere, and visible light is utilized to excite a photosensitizer for catalyzation. In a reaction solvent, ArNR1R2 as shown in a formula (1) and water as shown in a formula (2) are used as reaction raw materials and react under the auxiliary action of acid to obtain the aryl phenol compound as shown in a formula (3). The ArNR1R2 in the formula (1) can be primary amine and tertiary amine, can also be steroid and amino acid derivatives, and can also be drugs or derivatives of propofol, paracetamol, ibuprofen, oxaprozin, indomethacin and the like. The synthesis method has the advantages of cheap and easily available raw materials, simple reaction operation, mild reaction conditions, high reaction yield and good compatibility of substrate functional groups. The fluid reaction not only can realize amplification of basic chemicals, but also can realize amplification of fine chemicals, such as synthesis of drugs propofol and paracetamol. The invention has wide application prospect and use value.
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Paragraph 0100-0102
(2021/05/12)
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- Radical-anion coupling through reagent design: hydroxylation of aryl halides
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The design and development of an oxime-based hydroxylation reagent, which can chemoselectively convert aryl halides (X = F, Cl, Br, I) into phenols under operationally simple, transition-metal-free conditions is described. Key to the success of this approach was the identification of a reducing oxime anion which can interact and couple with open-shell aryl radicals. Experimental and computational studies support the proposed radical-nucleophilic substitution chain mechanism.
- Chechik, Victor,Greener, Andrew J.,James, Michael J.,Oca?a, Ivan,Owens-Ward, Will,Smith, George,Ubysz, Patrycja,Whitwood, Adrian C.
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p. 14641 - 14646
(2021/11/17)
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- Synthesis and Catalytic Properties of Metal- N-Heterocyclic-Carbene-Decorated Covalent Organic Framework
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We demonstrate herein that the N-heterocyclic-carbene (NHC)-metal complex (NHC-M)-involved covalent organic framework (COF) can be prepared by the direct polymerization of the NHC-M monomer with its counterpart under solvothermal conditions. The NHC-M-COF with different counterions is readily achieved via solid-state anion exchange. The obtained NHC-AuX-COF (X = Cl- and SbF6-) can be a highly active reusable catalyst to separately promote the carboxylation of the terminal alkyne with CO2 and alkyne hydration under mild conditions.
- Dong, Ying,Dong, Yu-Bin,Kan, Jing-Lan,Li, Yue,Wu, Xiaowei
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supporting information
p. 7363 - 7368
(2020/10/12)
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- Method for preparing alcohol and phenol through aerobic hydroxylation reaction of boric acid derivative in absence of photocatalyst
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The invention discloses a method for preparing alcohol and phenol through aerobic hydroxylation reaction of a boric acid derivative in the absence of a photocatalyst, wherein the boric acid derivativeis aryl boronic acid or alkyl boronic acid, and the corresponding target compounds are respectively a phenol-based compound and an alcohol-based compound. According to the method, by using a boric acid derivative as a reaction substrate, an additive is added under a solvent condition, and a hydroxylation reaction is performed under aerobic and illumination conditions to obtain a corresponding target compound. According to the invention, the new strategy is provided for the synthesis of phenols through aerobic hydroxylation of aryl boronic acid without a photocatalyst; the catalyst-free aerobic hydroxylation method for photocatalysis of aryl boronic acid or alkyl boronic acid by using triethylamine as an additive is firstly disclosed; and the new method has advantages of photocatalyst-freecondition, wide substrate range and good functional group compatibility.
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Paragraph 0025-0028; 0030-0032
(2020/01/25)
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- Preparation method of 3-hydroxyacetophenone
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The invention discloses a preparation method of 3-hydroxyacetophenone. The preparation method comprises the following steps of: S1, carrying out esterification reaction and hydroxyl protection reaction on 3-hydroxybenzoic acid, an esterification reagent, a protection reagent and strong acid to obtain a substance A; S2, reacting the substance A with dimethyl sulfoxide and an alkali reagent to obtain a substance B; and S3, reducing the substance B to obtain the 3-hydroxyacetophenone. The method has the advantages of readily available raw materials, short route, high yield, easiness in reaction operation and low environmental pollution, and is suitable for industrial production.
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Paragraph 0037; 0041-0045; 0049-0050; 0054-0055; 0059
(2020/11/12)
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- Preparation method for coproducing 3-hydroxyacetophenone and crystallized sulfanilamide
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The invention discloses a preparation method for co-producing 3-hydroxyacetophenone and crystallized sulfanilamide. The preparation method comprises the following steps: S1, taking 3-hydroxybenzoic acid, p-acetamidobenzenesulfonyl chloride and an acid-binding agent for condensation reaction to obtain a substance A; S2, performing acylating chlorination reaction on the substance A and an acylatingchlorination reagent to obtain a substance B; S3, taking the substance B to react with dimethyl malonate, magnesium chloride and triethylamine to obtain a substance C; S4, carrying out decarboxylationreaction on the substance C and an acidic substance, carrying out primary filtration, carrying out ammonolysis reaction on a primary filter cake and an aminating agent, adding an alkaline substance,carrying out amino deprotection reaction, crystallizing, carrying out secondary filtration, and taking a secondary filter cake to obtain crystallized sulfanilamide; and adjusting the pH value of the secondary filtrate to be less than 7, and crystallizing to obtain 3-hydroxyacetophenone. According to the preparation method, 3-hydroxybenzoic acid and p-acetamidobenzenesulfonyl chloride are taken asraw materials, two substances, namely 3-hydroxyacetophenone and crystallized sulfanilamide, are synchronously prepared, and the yield is relatively good.
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Paragraph 0045; 0047; 0052-0053; 0059; 0064-0065; 0066; 0071
(2020/08/02)
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- Cu(I)/sucrose-catalyzed hydroxylation of arenes in water: The dual role of sucrose
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A protocol for the hydroxylation of aryl halides catalyzed by copper(I) and sucrose in neat water has been developed. The dual role of sucrose, the reaction pathway, and the high selectivity for hydroxylation were investigated using a combination of experimental and theoretical techniques. This journal is
- Murata, Shigeo,Takagi, Mio,Takita, Ryo,Watanabe, Ayako,Watanabe, Kohei
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supporting information
p. 7827 - 7831
(2020/11/02)
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- Efficient solvent- And temperature-tuned access to aldoxime ethers and phenolic functions by Pd-catalyzed C-O cross-coupling of aldoximes with aryl bromides and bromo-chalcones
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A single method with a functionality switching option was developed for the first time for the Pd-catalyzed C-O cross-coupling of aryl bromides and bromo-chalcones with aldoximes. The ligand tBuXPhos (L2) was found to be an effective supporting ligand for the Pd-catalyzed coupling of aldoximes with bromo coupling partners. The functionality switching from oxime ethers to a phenolic or hydroxy group was driven by solvent or temperature. This method offers the products in good to excellent yields in short reaction times.
- Reeta,Rangarajan,Kaushik, Kumar,Singh, Rishi Pal,Singh, Manjula,Singh, Raj Pal
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supporting information
p. 1326 - 1336
(2020/02/11)
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- Palladium-Catalyzed Hydroxylation of Aryl Halides with Boric Acid
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Boric acid, B(OH)3, is proved to be an efficient hydroxide reagent in converting (hetero)aryl halides to the corresponding phenols with a Pd catalyst under mild conditions. Various phenol products were obtained in good to excellent yields. This transformation tolerates a broad range of functional groups and molecules, including base-sensitive substituents and complicated pharmaceutical (hetero)aryl halide molecules.
- Song, Zhi-Qiang,Wang, Dong-Hui
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supporting information
p. 8470 - 8474
(2020/11/18)
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- Oxalic amide ligands, and uses thereof in copper-catalyzed coupling reaction of aryl halides
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The present invention provides oxalic amide ligands and uses thereof in copper-catalyzed coupling reaction of aryl halides. Specifically, the present invention provides a use of a compound represented by formula I, wherein definitions of each group are described in the specification. The compound represented by formula I can be used as a ligand in copper-catalyzed coupling reaction of aryl halides for the formation of C—N, C—O and C—S bonds.
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Page/Page column 122
(2020/01/09)
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- Deracemization of sec-alcohols through sequential application of C. Albicans and Ketoreductases
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A biocatalytic cascade process was developed using immobilized cells of the wild type yeast Candida albicans CCT 0776 in calcium alginate beads and a commercially available ketoreductase. The aim was to promote deracemization by stereoinversion of (±)-1-arylethanols in high substrate concentration (above 100 mmol L-1) to prepare the (R)-enantiomers of the alcohols (90-99percent), with a high enantiomeric excess (83-99percent) after 2 to 19 h. The (R)-1-(3-methoxyphenyl)ethanol, with 70percent yield and 91percent ee, obtained after 5 h was used to prepare (S)-1-(3-methoxyphenyl)-ethylamine with 60percent yield and 91percent ee after two steps, a key intermediate in the synthesis of (S)-rivastigmine.
- Nasário, Fábio D.,Moran, Paulo J.S.,Rodrigues, José Augusto R.
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p. 772 - 779
(2019/08/26)
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- Photoinduced hydroxylation of arylboronic acids with molecular oxygen under photocatalyst-free conditions
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Photoinduced hydroxylation of boronic acids with molecular oxygen under photocatalyst-free conditions is reported, providing a green entry to a variety of phenols and aliphatic alcohols in a highly concise fashion. This new protocol features photocatalyst-free conditions, wide substrate scope and excellent functional group compatibility.
- Xu, Yu-Ting,Li, Chen-Yuan,Huang, Xiao-Bo,Gao, Wen-Xia,Zhou, Yun-Bing,Liu, Miao-Chang,Wu, Hua-Yue
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supporting information
p. 4971 - 4975
(2019/09/30)
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- Tropylium Ion Catalyzes Hydration Reactions of Alkynes
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The hydration of alkynes is one of the most atom-economic and versatile synthetic protocols to access carbonyl compounds. This fundamental reaction, however, often requires transition-metal catalysts or harsh reaction conditions to promote the addition of water to the carbon–carbon triple bond. In this work, it is demonstrated that the non-benzenoid aromatic tropylium ion can be used as an organic Lewis acid promoter for the hydration of alkynes under simple reaction conditions with excellent outcomes.
- Oss, Giulia,Ho, Junming,Nguyen, Thanh Vinh
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supporting information
p. 3974 - 3981
(2018/08/17)
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- M-hydroxy acetophenone preparation method
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The invention discloses an m-hydroxy acetophenone preparation method which includes the steps: performing chlorination, dissolving m-hydroxybenzoic acid in methylbenzene, adding 4-dimethylamino pyridine serving as a catalyst, adding acyl thionyl chloride for chlorination to obtain m-hydroxybenzoic acid acyl chloride, and then removing the acyl thionyl chloride by concentration and evaporation to obtain m-hydroxybenzoic acid acyl chloride-methylbenzene solution; dissolving dimethyl malonate sodium salt in methylbenzene to obtain dimethyl malonate sodium salt-methylbenzene solution, dripping them-hydroxybenzoic acid acyl chloride-methylbenzene solution obtained in the step (1) into the dimethyl malonate sodium salt-methylbenzene solution, and then performing reflux reaction for 3-5 hours atthe reaction temperature of 50-80 DEG C to obtain a product A; adding the obtained product A into hydrochloric acid solution, and performing hydrolysis reaction to obtain m-hydroxy acetophenone. Thepreparation method is simple in process, small in wastewater discharge amount, low in cost and high in yield and final product purity.
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Paragraph 0030; 0031; 0032; 0033; 0034; 0035; 0036-0058
(2018/10/26)
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- Ozonation of ketoprofen with nitrate in aquatic environments: Kinetics, pathways, and toxicity
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In this study, nitrate ion (NO3-) was found to collaborate with ozone thereby accelerating the degradation of ketoprofen. NO3- was discovered to induce the generation of hydroxyl radicals (·OH), which was crucial to the decomposition of PPCPs in wastewater treatment plants. Kinetic studies on the decomposition of ketoprofen were investigated under different concentrations of NO3-. The impact mechanisms and degradation by-products were experimentally determined. The results revealed that all reactions fitted the pseudo-first-order kinetic model well. The presence of NO3- had the capacity to accelerate the ozonation of ketoprofen. The reaction by-products were evaluated by UPLC-Q-TOF-MS, and a total of five intermediates generated via the ozonation of ketoprofen were assessed. The transformation pathways were concluded to be hydroxylation, nitration, and debenzophenone and ketonized reactions. Additionally, the toxicity of the by-products was evaluated by employing Chlorella and Daphnia magna.
- Zeng, Yongqin,Lin, Xiaoxuan,Li, Fuhua,Chen, Ping,Kong, Qingqing,Liu, Guoguang,Lv, Wenying
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p. 10541 - 10548
(2018/03/26)
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- Deprotection of durable benzenesulfonyl protection for phenols — efficient synthesis of polyphenols
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A robust protection method for phenol was demonstrated by the use of durable benzenesulfonyl group, which survives various harsh reaction conditions using Grignard reagent, organolithium reagent, metal alkoxide, phosgene, mineral, and Lewis acids. A facile deprotection condition utilizing pulverized KOH (5 equiv) and t-BuOH (10 equiv) in hot toluene makes this protocol as a practical method, which can be applied to the multistep synthesis of biologically and medicinally important polyphenol compounds.
- Alam, Mohammad Shariful,Koo, Sangho
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supporting information
p. 247 - 254
(2018/01/08)
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- Synthesis of Phenols: Organophotoredox/Nickel Dual Catalytic Hydroxylation of Aryl Halides with Water
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A highly effective hydroxylation reaction of aryl halides with water under synergistic organophotoredox and nickel catalysis is reported. The OH group of the resulting phenols originates from water, following deprotonation facilitated by an intramolecular base group on the ligand. Significantly, aryl bromides as well as less reactive aryl chlorides served as effective substrates to afford phenols with a wide range of functional groups. Without the need for a strong inorganic base or an expensive noble-metal catalyst, this process can be applied to the efficient preparation of diverse phenols and enables the hydroxylation of multifunctional pharmaceutically relevant aryl halides.
- Yang, Liu,Huang, Zhiyan,Li, Gang,Zhang, Wei,Cao, Rui,Wang, Chao,Xiao, Jianliang,Xue, Dong
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supporting information
p. 1968 - 1972
(2018/02/06)
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- C70 Fullerene-Catalyzed Metal-Free Photocatalytic ipso-Hydroxylation of Aryl Boronic Acids: Synthesis of Phenols
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A metal-free C70 fullerene-catalyzed method has been developed for the ipso-hydroxylation of aryl and heteroaryl boronic acids to corresponding phenols under photocatalytic conditions. The reaction proceeds under oxygen atmosphere and the mechanistic study revealed that C70 plays a critical role in the generation of reactive oxygen species in the presence of blue light. Reactions in the presence of 18O-labelled water and oxygen confirmed the generation of reactive oxygen species from oxygen molecule. Amine used as a reductant could be recovered in the form of imine. The current method is also applicable to the synthesis of aryl ethers in one-pot two-step process. (Figure presented.).
- Kumar, Inder,Sharma, Ritika,Kumar, Rakesh,Kumar, Rakesh,Sharma, Upendra
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supporting information
p. 2013 - 2019
(2018/04/02)
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- 8,10,12 as nanoreactors for non-enzymatic introduction of: Ortho, meta or para -hydroxyl groups to aromatic molecules
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Traditional electrophilic bromination follows long established "rules": electron-withdrawing substituents cause bromination selective for meta positions, whereas electron-donating substituents favor ortho and para bromination. In contrast, in the [PhSiO1.5]8,10,12 silsesquioxanes, the cages act as bulky, electron withdrawing groups equivalent to CF3; yet bromination under mild conditions, without a catalyst, greatly favors ortho substitution. Surprisingly, ICl iodination without a catalyst favors (>90%) para substitution [p-IC6H4SiO1.5]8,10,12. Finally, nitration and Friedel-Crafts acylation and sulfonylation are highly meta selective, >80%. In principle, the two halogenation formats coupled with the traditional electrophilic reactions provide selective functionalization at each position on the aromatic ring. Furthermore, halogenation serves as a starting point for the synthesis of two structural isomers of practical utility, i.e. in drug prospecting. The o-bromo and p-iodo compounds are easily modified by catalytic cross-coupling to append diverse functional groups. Thereafter, F-/H2O2 treatment cleaves the Si-C bonds replacing Si with OH. This represents a rare opportunity to introduce hydroxyl groups to aromatic rings, a process not easily accomplished using traditional organic synthesis methods. The as-produced phenol provides additional opportunities for modification. Each cage can be considered a nanoreactor generating 8-12 product molecules. Examples given include syntheses of 4,2′-R,OH-stilbenes and 4,4′-R,OH-stilbenes (R = Me, CN). Unoptimized cleavage of the Br/I derivatives yields 55-85% phenol. Unoptimized cleavage of the stilbene derivatives yields 35-40% (3-5 equivalents of phenol) in the preliminary studies presented here. In contrast, meta R-phenol yields are 80% (7-10 mol per cage).
- Bahrami, Mozhgan,Zhang, Xingwen,Ehsani, Morteza,Jahani, Yousef,Laine, Richard M.
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supporting information
p. 8797 - 8808
(2017/07/22)
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- Photocatalytic benzene and benzene derivative direct hydroxylation or amination method
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The invention discloses a photocatalytic benzene and benzene derivative direct hydroxylation or amination method. The method is characterized by comprising the following steps: (1) adding a photo-sensitizer and a cobalt catalyst into a solvent to obtain a solution (A); (2) adding benzene (or benzene derivatives), water, ammonia gas, and amide derivatives (or sulfonamide derivatives) into the solution (A) to obtain a solution (B); and (3) in a N2 (or Ar) environment, radiating the solution (B) by a medium pressure mercury lamp, a high pressure mercury lamp, a xenon lamp, or an LED lamp to obtain phenols or amines and H2. For the first time, a photo-sensitizer and a cobalt catalyst are combined and applied to photocatalytic hydroxylation and amination of benzene. The conditions of the method are mild, light is taken as the driving energy, no oxidant is added, the only byproduct is H2, and the whole process is green, concise, and efficient. High selective benzene one-step hydroxylation to generate phenol or high selective phenol/benzene one-step amination to generate aniline is realized, and the method can be applied to the production of phenol and aniline.
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Paragraph 0112-0113
(2017/11/29)
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- A method for the preparation of meta-hydroxy acetophenone (by machine translation)
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The invention discloses a method for the preparation of meta-hydroxy acetophenone, comprises the following steps: the hydroxy benzoic acid acetylation by second grade acyloxy benzoic acid, benzoyl chloride is obtained and then the second grade acyloxy acyl, then with malonic acid diethyl ester sodium salt solution reaction to obtain 3 - acetoxy benzoyl c diethyl malonate, finally decarboxylates and gets meta-hydroxy acetophenone. The operation of the invention is simple, and cheap raw material, synthetic easy, less side reaction, with a higher yield. (by machine translation)
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Paragraph 0059; 0065; 0071; 0077; 0083; 0089; 0095-0098
(2017/09/18)
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- Selective oxidation of aliphatic C-H bonds in alkylphenols by a chemomimetic biocatalytic system
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Selective oxidation of aliphatic C-H bonds in alkylphenols serves significant roles not only in generation of functionalized intermediates that can be used to synthesize diverse downstream chemical products, but also in biological degradation of these environmentally hazardous compounds. Chemo-, regio-, and stereoselectivity; controllability; and environmental impact represent the major challenges for chemical oxidation of alkylphenols. Here, we report the development of a unique chemomimetic biocatalytic system originated from the Gram-positive bacterium Corynebacterium glutamicum. The system consisting of CreHI (for installation of a phosphate directing/ anchoring group), CreJEF/CreG/CreC (for oxidation of alkylphenols), and CreD (for directing/anchoring group offloading) is able to selectively oxidize the aliphatic C-H bonds of p-And m-Alkylated phenols in a controllable manner. Moreover, the crystal structures of the central P450 biocatalyst CreJ in complex with two representative substrates provide significant structural insights into its substrate flexibility and reaction selectivity.
- Du, Lei,Dong, Sheng,Zhang, Xingwang,Jiang, Chengying,Chen, Jingfei,Yao, Lishan,Wang, Xiao,Wan, Xiaobo,Liu, Xi,Wangi, Xinquan,Huang, Shaohua,Cui, Qiu,Feng, Yingang,Liu, Shuang-Jiang,Li, Shengying
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p. E5129 - E5137
(2017/07/04)
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- Synthesis of phenols by using aryldiazonium silica sulfate nanocomposites
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The hydrolysis of a new type of diazonium salt immobilized on the surface of silica sulfuric acid was studied in this work. By using diazonium salt nanocomposites, a number of phenol derivatives were synthesized in good yields. In contrast to the previous works, the present procedure was conveniently carried out under mild and solvent-free conditions. The effects of solvent and temperature were studied on the dediazoniation products. The notable advantages of this methodology were operational simplicity, availability of reactants, short reaction time and easy work-up.
- Zarei, Amin,Khazdooz, Leila,Aghaei, Hamidreza,Gheisari, Mohammad Mehdi,Alizadeh, Shahrzad,Golestanifar, Laleh
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supporting information
p. 6954 - 6961
(2017/11/16)
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- Metal-Free Markovnikov-Type Alkyne Hydration under Mild Conditions
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A Markovnikov-type alkyne hydration protocol is presented using 20% CF3SO3H (TfOH) as the catalyst under unprecedented mild conditions applicable to various alkynes, including terminal arylalkynes, terminal nonfunctionalized aliphatic alkynes, and internal alkynes with excellent regioselectivity in good to excellent yields (average yields >85%). The reaction procedure operates under mild conditions (25-70°C), with broad functional group compatibility, and uses only slightly more than a stoichiometric amount of water in the absence of any transition metal. The success of this protocol hinges upon the utilization of trifluoroethanol as the solvent.
- Liu, Wenbo,Wang, Haining,Li, Chao-Jun
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supporting information
p. 2184 - 2187
(2016/06/01)
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- Photocatalytic Hydrogen-Evolution Cross-Couplings: Benzene C-H Amination and Hydroxylation
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We present a blueprint for aromatic C-H functionalization via a combination of photocatalysis and cobalt catalysis and describe the utility of this strategy for benzene amination and hydroxylation. Without any sacrificial oxidant, we could use the dual catalyst system to produce aniline directly from benzene and ammonia, and phenol from benzene and water, both with evolution of hydrogen gas under unusually mild conditions in excellent yields and selectivities.
- Zheng, Yi-Wen,Chen, Bin,Ye, Pan,Feng, Ke,Wang, Wenguang,Meng, Qing-Yuan,Wu, Li-Zhu,Tung, Chen-Ho
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supporting information
p. 10080 - 10083
(2016/09/04)
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- Preparation method of 2-bromo-3'-methoxyacotophenone
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The invention relates to a preparation method of a medical intermediate, in particular to a preparation method of 2-bromo-3'-methoxyacotophenone. According to the preparation method, the target product is prepared by taking acetophenone, dimethyl sulfate and a brominating agent as main raw materials through the steps of a nitration reaction, a reduction reaction, a diazotization reaction, a hydrolysis reaction, a methylation reaction, a bromination reaction and the like. The preparation method has the advantages that the yields of the reactions are all 80% or above, the purity of the obtained target product 2-bromo-3'-methoxyacotophenone can reach 99.2%, the cost is low, and the yield and the purity are high; in the preparation process, the reaction conditions are mild, operation is easy, little harm is generated to the environment, and the preparation method is suitable for large-scale production.
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- 3-hydroxyacetophenone synthesis method
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The invention provides a 3-hydroxyacetophenone synthesis method. The method includes the steps that 3-hydroxybenzoic acid is subjected to hydroxyl protection through an esterification or etherification reaction, then a chloroformylation reaction and an alkylation reaction are conducted, finally hydrolysis is conducted, and the 3-hydroxyacetophenone is obtained. According to the method, raw materials are cheap, easy to obtain and wide in source, high-temperature and high-pressure operation does not exist, equipment requirement is low, and equipment investment is low; peroxide, heavy nitride and the like do not exist, and high safety is achieved; compared with a nitration-iron powder reduction-diazotization route commonly adopted in the nation, the synthesis method has huge environment-friendly advantages. Besides, according to the method, the amount of wastewater is less than 5% that of an original process, the total route yield is 90%, and the method has huge technological advantages.
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Paragraph 0057; 0061
(2017/01/12)
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- One pot synthesis of α-ketoamides from ethylarenes and amines: a metal free difunctionalization strategy
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One-pot and metal free synthesis of α-ketoamides has been described through in situ generation of aryl ketones from easily available ethylarenes followed by amidation with various amines. This multiple oxidation protocol involves catalytic I2-pyridine-TBHP (t-butyl hydroperoxide) mediated oxidative benzylic carbonylation and sequential NaI-TBHP mediated oxidative amidation without using any solvent.
- Ramanathan, Mani,Kuo, Chun-Kai,Liu, Shiuh-Tzung
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p. 11446 - 11453
(2016/12/16)
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- Deracemization of 1-phenylethanol via tandem biocatalytic oxidation and reduction
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(R)-1-Arylethanols and other secondary alcohols were prepared at high ee (>90%) by oxidative kinetic resolution using resting cells of the yeast Candida albicans CCT 0776. The deracemization process of 1-phenylethanol 1a catalyzed by the yeast was elucidated by studying each step separately. It was determined that the reaction occurred via cyclic deracemization, to give (R)-1a in 89% yield and with 98% ee. Finally, deracemization by stereoinversion of rac-1a was studied using a tandem process of C. albicans followed by Lactobacillus brevis CCT 3745. Inverting the sequence of these microorganisms produced an enantiomerically pure antipode.
- Nasário, Fábio D.,Cazetta, Tarcila,Moran, Paulo J.S.,Rodrigues, J. Augusto R.
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p. 404 - 409
(2016/05/19)
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- Copper-Catalyzed Hydroxylation of (Hetero)aryl Halides under Mild Conditions
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The combination of Cu(acac)2 and N,N′-bis(4-hydroxyl-2,6-dimethylphenyl)oxalamide (BHMPO) provides a powerful catalytic system for hydroxylation of (hetero)aryl halides. A wide range of (hetero)aryl chlorides bearing either electron-donating or -withdrawing groups proceeded well at 130 °C, delivering the corresponding phenols and hydroxylated heteroarenes in good to excellent yields. When more reactive (hetero)aryl bromides and iodides were employed, the hydroxylation reactions completed at relatively low temperatures (80 and 60 °C, respectively) at low catalytic loadings (0.5 mol % Cu).
- Xia, Shanghua,Gan, Lu,Wang, Kailiang,Li, Zheng,Ma, Dawei
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supporting information
p. 13493 - 13496
(2016/10/31)
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- A Mild Strategy for the Preparation of Phenols via the Ligand-Free Copper-Catalyzed O-Arylation of para -Toluenesulfonic Acid
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A facile and simple ligand-free copper-catalyzed reaction to synthesize substituted phenols is reported. The reaction presumably proceeds via an O-arylsulfonate intermediate that is hydrolyzed to afford good to excellent yields of up to 88%. This protocol provides an alternative to existing reports which use strong hydroxide salts as the direct hydroxylation partner. Demonstrating a wide substrate scope and functional group tolerance, this protocol can also be applied to inexpensive and commercially available carboxylic acids to yield phenols.
- Tan, Bryan Yong-Hao,Teo, Yong-Chua
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supporting information
p. 1814 - 1819
(2016/07/16)
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- Direct hydroxylation of arenes with O2 catalyzed by V@CN catalyst
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A vanadium doped graphitic carbon nitride catalyst has been prepared and used for the direct hydroxylation of arenes with O2. Substituted arenes with electron-withdrawing groups such as CN, NO2, COOH, CF3, and COCH3 were oxygenated to the corresponding phenols in moderate yields. The catalyst also proved applicable for the hydroxylation of aromatic halides (F, Cl, and Br) with O2.
- Li, Yan,Li, Bing,Chen, Ting,Zhou, Zhicheng,Wang, Jun,Huang, Jun
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p. 1086 - 1092
(2015/07/01)
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- The Hydroxylation of Aromatics with Oxygen by Vanadium Catalysts Supported on N-doped Carbon Materials
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Vanadium catalysts supported on N-doped carbon materials (CN) were prepared and the catalyst VOSiW showed high activity for the hydroxylation of various aromatics with O2. Aromatics with electron-withdrawing groups such as CN, NO2, COOH, CF3, COCH3 and aromatic halides (F, Cl and Br) were oxygenated to the corresponding phenols in considerable yields. The CN materials were not only indispensable for the reusability of the vanadium catalyst VOSiW, but also favorable to the high catalytic activity. The VOSiW catalyst is ready for the hydroxylation of aromatics with O2 as both V4+ and V5+ species are coexisted in the VOSiW catalyst.
- Li, Yan,Li, Bing,Geng, Longfei,Wang, Jun,Wang, Yong,Huang, Jun
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p. 1014 - 1021
(2015/08/04)
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- Hydrolysis of diazonium salts using a two-phase system (CPME and water)
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A new method for the hydrolysis of diazonium salts, without the formation of tar, was developed. A two-phase system consisting of cyclopentyl methyl ether (CPME) and water is very effective for the hydrolysis of diazonium salts. Using this solvent system, the diazonium salt prepared from 3-(4-nitrophenoxy)aniline gave 3-(4-nitrophenoxy)phenol in high yield (96%) within 20 min. The synthesized phenol is an industrially important raw material in polymer syntheses. Furthermore, the use of the present two-phase system of CPME and water successfully brought about the efficient conversions of several m-substituted anilines into the corresponding m-substituted phenols. This is the first example of hydrolysis of diazonium salts using the two-phase system (CPME and water).
- Taniguchi, Toshihide,Imoto, Mitsutaka,Takeda, Motonori,Nakai, Takeo,Mihara, Masatoshi,Iwai, Toshiyuki,Ito, Takatoshi,Mizuno, Takumi,Nomoto, Akihiro,Ogawa, Akiya
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p. 411 - 416
(2018/01/18)
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- Reaction of 1,2-difunctionalized ethanes with aryl iodides in copper-catalyzed cross-coupling: Application to synthesis of phenols
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A series of 1,2-difunctionalized ethanes, such as ethylene glycol, 2-aminoethanol, 1,2-diaminoethane, 2-dimethylaminoethanol N',N'-dimethylethane-1,2-diamine, were investigated to test the reactivity with aryl iodides in the presence of copper catalysts. Under the reaction conditions, they produce the various Cheteroatom cross-coupled products. Interestingly, ethylene glycol and 2-dimethylaminoethanol afforded mainly the phenolic compounds while the others produced different cross-coupled products. Although ethylene glycol and 2-dimethylaminoethanol resulted in the same product, their behaviors in the reaction were quite different: ethylene glycol appears to mostly act as the ligand and 2-dimethylaminoethanol appears to serve as both the ligand and reactant. This finding led to a copper-catalyzed synthesis of phenols using either ethylene glycol or 2-dimethylaminoethanol, which can be applied to a variety of aryl iodides, providing an alternative synthetic route to phenols.
- Kim, Jihye,Battsengel, Oyunsaikhan,Liu, Yajun,Chae, Junghyun
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supporting information
p. 2833 - 2840
(2016/02/05)
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- Highly efficient deprotection of phenolic tetrahydropyranyl and methoxymethyl ethers and sequel cyclization to indanones using Sn(IV)Cl 4 catalyst
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Sn(IV)Cl4 catalyst provided a rapid and efficient deprotection method for the phenolic THP and MOM ethers and sequel intramolecular Friedel-Crafts alkylation reaction of THP and MOM protected chalcone epoxides under mild conditions. The reaction took 2-3 min to give the products in excellent yield (90-98%) at 0 °C without affecting the other functional groups.
- Ahmed, Naseem,Pathe, Gulab Khushalrao,Venkata Babu
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supporting information
p. 3683 - 3687
(2014/06/23)
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- Hydration of aromatic terminal alkynes catalyzed by iron(III) sulfate hydrate under chlorine-free conditions
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The hydration of aromatic terminal alkynes performed in acetic acid in the presence of catalytic hydrate ironIII sulfate, Fe2(SO 4)3·nH2O (4-9 mol %), yields the derived aryl methyl ketones with good to excellent yields. Under comparable conditions (18 mol %, 95 C, 24 h), bifunctional substrates were transformed into the monoacetyl or the diacetyl derivatives, depending on the structure of the aromatic diyne. The reaction is compatible with aryl substituents of different nature and ring positions, including hydroxyl, carbonyl groups, and cumulated hydrocarbons. The soft character of the non nucleophilic sulfate anion allows for activation of the triple bond toward carbonoxygen bond formation in the Br?nsted acidic medium. The proposed protocol is based on readily available and non toxic materials, in the absence of chlorine atoms in either the solvent or the metal catalyst.
- Bassetti, Mauro,Ciceri, Samuele,Lancia, Federico,Pasquini, Chiara
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supporting information
p. 1608 - 1612
(2014/03/21)
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- Triethanolamine as an inexpensive and efficient ligand for copper-catalyzed hydroxylation of aryl halides in water
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The CuI/triethanolamine catalyst system efficiently promotes the direct hydroxylation of aryl iodides and bromides in water to provide the corresponding phenols in good to excellent yields. Moreover, the procedure avoids the use of toxic organic solvents and tolerates many functional groups. The CuI/triethanolamine catalyst system efficiently promotes the direct hydroxylation of aryl iodides and bromides in water to afford the corresponding phenols in good to excellent yields. Copyright
- Wang, Deping,Kuang, Daizhi,Zhang, Fuxing,Tang, Siping,Jiang, Wujiu
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supporting information
p. 315 - 318
(2014/01/23)
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- Triethanolamine as an Inexpensive and Efficient Ligand for Copper-Catalyzed Hydroxylation of Aryl Halides in Water
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The CuI/triethanolamine catalyst system efficiently promotes the direct hydroxylation of aryl iodides and bromides in water to provide the corresponding phenols in good to excellent yields. Moreover, the procedure avoids the use of toxic organic solvents and tolerates many functional groups.
- Wang, Deping,Kuang, Daizhi,Zhang, Fuxing,Tang, Siping,Jiang, Wujiu
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supporting information
p. 315 - 318
(2015/10/05)
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- Unexpected hydrazine hydrate-mediated aerobic oxidation of aryl/ heteroaryl boronic acids to phenols in ambient air
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The expedient and efficient sub-stoichimetric hydrazine hydrate-mediated aerobic hydroxylation of boronic acids that proceeds in poly(ethylene glycol) (PEG-400) has been successfully developed, providing diverse phenols in high yields. And heteroaryl boronic acids are also amenable to this protocol. the Partner Organisations 2014.
- Zhong, Yanzhen,Yuan, Linxin,Huang, Zheng,Gu, Wenchao,Shao, Ye,Han, Wei
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p. 33164 - 33167
(2014/08/18)
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- Iron-catalyzed indirect hydration of alkynes in presence of methanesulfonic acid
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We have demonstrated that the FeCl2·4H2O and methanesulfonic acid systems show high reaction efficiency for the indirect hydration of various alkynes in DCE. The reaction proceeds under mild conditions to produce various ketones from alkynes. A mechanistic study of the reaction intermediates showed that the alkyne was readily converted into vinyl sulfonate corresponding to the addition of MsOH to the C-C triple bonds, which in turn was transformed to the ketone in the presence of MsOH.
- Park, Jungmin,Yeon, Jihee,Lee, Phil Ho,Lee, Kooyeon
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p. 4414 - 4417
(2013/07/26)
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- Leaving-group substituent controls reactivity and reaction mechanism in aminolysis of phenyl y-substituted-phenyl carbonates
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A kinetic study is reported for the nucleophilic substitution reactions of phenyl Y-substituted-phenyl carbonates (5a-5k) with piperidine in 80 mol % H2O/20 mol % DMSO at 25.0 ± 0.1 °C. The plots of k obsd vs. [piperidine] for the reactions of substrates possessing a strong electron-withdrawing group (EWG) in the leaving group (i.e., 5a-5i) are linear and pass through the origin. In contrast, the plots for the reactions of substrates bearing a weak EWG or no substituent (i.e., 5j or 5k) curve upward, indicating that the electronic nature of the substituent Y in the leaving group governs the reaction mechanism. Thus, it has been suggested that the reactions of 5a-5i proceed through a stepwise mechanism with a zwitterionic tetrahedral intermediate (i.e., T±) while those of 5j and 5k proceed through a stepwise mechanism with two intermediates (i.e., T± and its deprotonated form T-). The slope of the Bronsted-type plot for the second-order rate constants (i.e., kN or Kk2) changes from -0.41 to -1.89 as the leaving-group basicity increases, indicating that a change in the rate-determining step (RDS) occurs. The reactions of 5a-5k with piperidine result in larger k1 values than the corresponding reactions with ethylamine. Copyright
- Kang, Ji-Sun,Song, Yoon-Ju,Um, Ik-Hwan
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p. 2023 - 2028
(2013/09/02)
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- A kinetic study on ethylaminolysis of phenyl y-substituted-phenyl carbonates: Effect of leaving-group substituents on reactivity and reaction mechanism
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A kinetic study on nucleophilic substitution reactions of phenyl Y-substituted-phenyl carbonates (5a-5j) with ethylamine in 80 mol % H2O/20 mol % DMSO at 25.0 ± 0.1 oC is reported. The plots of kobsd vs. [amine] are linear for the reactions of substrates possessing a strong electron-withdrawing group (EWG) but curve upward for those of substrates bearing a weak EWG, indicating that the electronic nature of the substituent Y in the leaving group governs the reaction mechanism. The reactions have been concluded to proceed through a stepwise mechanism with one or two intermediates (a zwitterionic tetrahedral intermediate T± and its deprotonated form T-) depending on the nature of the substituent Y. Analysis of Bronsted-type plots and dissection of kobsd into microscopic rate constants have revealed that the reactions of substrates possessing a strong EWG (e.g., 5a-5f) proceed through T± with its formation being the rate-determining step, while those of substrates bearing a weak EWG (e.g., 5g-5j) proceed through T± and T-.
- Song, Yoon-Ju,Kim, Min-Young,Um, Ik-Hwan
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p. 1722 - 1726
(2013/07/26)
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