- Unprecedented Regioregular Poly(1,4-arylene)s Prepared by Nickel(II)-Catalyzed Cross-Coupling Polymerization of 2,5-Disubstituted Bromo(chloro)arylene
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The unprecedented synthesis of regioregular head-to-tail-type poly(1,4-arylene)s bearing different substituents at the 2- and 5-positions is described. They were prepared by the polymerization of 2,5-disubstituted bromo(chloro)arylenes by selective halogen–metal exchange with a Grignard reagent and subsequent cross-coupling polymerization with a nickel catalyst [NiCl2(dppp)]. Formation of the regioregular poly(1,4-arylene)s were confirmed by NMR spectroscopy, and showed remarkable differences to those polymers having uncontrolled regioregularity. Polymerization of bromo(chloro)arylenes with a chiral alkoxy substituent also led to the regioregular head-to-tail-type polyarylene, which demonstrated circular dichroism, thus suggesting formation of a structure with higher-order regularity.
- Shibuya, Yushin,Nakagawa, Naoki,Miyagawa, Naoki,Suzuki, Toyoko,Okano, Kentaro,Mori, Atsunori
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- Synthetic method 4 - alkoxyphenol compounds
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The invention discloses a synthetic method of 4 - alkoxyphenol compounds, and belongs to the field of organic chemical synthesis. The method is as follows: An aryl alkyl ether compound is added to the sealing tube. The catalyst dimerization acetic acid rhodium and the oxidizing agent iodobenzene diethyl ester are added, a solvent trifluoroacetic anhydride is added, and the 4 -alkoxyphenol compound is prepared by heating reaction. To the invention, high regioselectivity direct hydroxylation of the aryl alkyl ether compound is realized, the application range of the substrate is wide, the yield is high, the activity after amplification reaction does not significantly decay, and higher yield is still obtained. The utility model has good practicability and industrial application prospect.
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Paragraph 0085-0087
(2021/09/29)
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- Para -Selective hydroxylation of alkyl aryl ethers
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para-Selective hydroxylation of alkyl aryl ethers is established, which proceeds with a ruthenium(ii) catalyst, hypervalent iodine(iii) and trifluoroacetic anhydride via a radical mechanism. This protocol tolerates a wide scope of substrates and provides a facile and efficient method for preparing clinical drugs monobenzone and pramocaine on a gram scale.
- Zhu, Runqing,Sun, Qianqian,Li, Jing,Li, Luohao,Gao, Qinghe,Wang, Yakun,Fang, Lizhen
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supporting information
p. 13190 - 13193
(2021/12/16)
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- 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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p. 8127 - 8131
(2021/08/23)
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- Regioselective synthesis of gentisyl alcohol-type marine natural products
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Gentisyl alcohol-type natural products, possessing various important biological properties, have been synthesized from 4-methoxyphenol by using a selective phenol monohydroxymethylation/monochlorination, a CAN oxidation and a sodium dithionite reduction as the key steps. The natural product synthesis is efficient, atom- and step-economical, and requires no protecting groups.
- Wang, Hong-Shuang,Li, Hui-Jing,Wang, Long-Fei,Shen, Zhi-Lun,Wu, Yan-Chao
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supporting information
p. 1891 - 1896
(2018/05/29)
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- Regioselective C-H chlorination: Towards the sequential difunctionalization of phenol derivatives and late-stage chlorination of bioactive compounds
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We have developed a protocol for the auxillary directed C-H chlorination of phenol derivatives using catalytic amounts of palladium acetate that is amenable to the late-stage chlorination of diflufenican and estrone. The 2-pyridine group allows for a highly efficient palladium-catalyzed chlorination and sequential ortho C-H functionalization reaction of phenol derivatives to produce a variety of symmetrical and unsymmetrical 2,4,6-trisubstituted phenols.
- Gao, Chao,Li, Hongchen,Liu, Miaochang,Ding, Jinchang,Huang, Xiaobo,Wu, Huayue,Gao, Wenxia,Wu, Ge
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p. 46636 - 46643
(2017/10/16)
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- Unanticipated participation of HCl in nucleophilic chlorination reaction: Expedient route to meta chlorophenols
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o-Quinone monoketals participated in a 1,4-addition reaction with HCl furnishing m-chlorophenols in high yields. Several readily available o-quinone monoketals were selected to display the generality of this serendipitous and unprecedented reaction and the results are presented herein.
- Chittimalla, Santhosh Kumar,Bandi, Chennakesavulu
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supporting information
p. 15 - 19
(2015/12/23)
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- Highly Selective Synthesis of Chlorophenols under Microwave Irradiation
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Oxychlorination of various phenols is finished in 60 minutes with high efficiency and perfect selectivity under microwave irradiation. These reactions adopt copper(II) chloride (CuCl2) as the catalyst and hydrochloric acid as chlorine source instead of expensive and toxic ones. Oxychlorination of phenols substituted with electron donating groups (methyl, methoxyl, isopropyl, etc.) at ortho- and meta-positions is accomplished with higher conversion rates, lower reaction time, and excellent selectivity. A proposed reaction mechanism is deduced; one electron transfers from CuCl2 to phenol followed by the formation of tautomeric radical that can be rapidly captured by chlorine atom and converts into para-substituted product.
- Xiong, Yawen,Duan, Hongdong,Meng, Xia,Ding, Zhaoyun,Feng, Weichun
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- Metal-Free [3+2] Oxidative Coupling of Phenols with Alkenes: Synthesis of Dihydrobenzofurans
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Herein, we demonstrated a benign and metal-free [3+2]-cycloaddition reaction using simple and readily available phenols and styrenes as substrates and sodium persulfate as an inexpensive and environmentally friendly oxidant for the direct synthesis of dih
- Zhao, Yating,Huang, Binbin,Yang, Chao,Li, Bing,Xia, Wujiong
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p. 2731 - 2737
(2015/09/15)
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- Synthesis of o-chlorophenols via an unexpected nucleophilic chlorination of quinone monoketals mediated by N,N′-dimethylhydrazine dihydrochloride
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An unexpected nucleophilic chlorination of a quinone monoketal while carrying out a pyrazolidine synthesis has led to a general preparation of multisubstituted phenols. The products are obtained in good to high yields under mild conditions. The bridged pyrazolidines that were the original targets are obtained in the presence of a protic solvent. This journal is the Partner Organisations 2014.
- Yin, Zhiwei,Zhang, Jinzhu,Wu, Jing,Green, Riana,Li, Sihan,Zheng, Shengping
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p. 2854 - 2858
(2014/05/06)
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- Multicomponent multicatalyst reactions (MC)2R: One-pot synthesis of 3,4-dihydroquinolinones
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A Rh/Pd/Cu catalyst system led to an efficient synthesis of dihydroquinolinones in one-pot, two operations. The reaction features the first triple metal-catalyzed transformations in one reaction vessel, without any intermediate workup. The conjugate-addition/amidation/amidation reaction sequence is highly modular, divergent, and practical.
- Zhang, Lei,Sonaglia, Lorenzo,Stacey, Jason,Lautens, Mark
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supporting information
p. 2128 - 2131
(2013/06/05)
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- Design, synthesis and biological evaluation of novel pyrimidine, 3-cyanopyridine and m-amino-N-phenylbenzamide based monocyclic EGFR tyrosine kinase inhibitors
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36 new compounds with the typical skeleton of 4-anilino-5-vinyl/ethynyl pyrimidine, 4-anilino-3-cyano-5-vinyl/ethynyl/phenyl pyridine, and m-amino-N-phenylbenzamide, are designed, synthesized and selectively tested on EGFR, ErbB-2 kinases, and A-549, HL60 cells growth inhibition. Results from the bioactivity and chemical structures yield preliminary structure-activity relationships (SARs). The most potent 5-ethynylpyrimidine derivative 20a has an IC50 value of 45 nM to EGFR kinase. Several compounds of other series also show IC50 values 1 μM for EGFR and 5 μM for A-549 and HL60 cells growth inhibition.
- Mao, Yongjun,Zhu, Wenxiu,Kong, Xiaoguang,Wang, Zhen,Xie, Hua,Ding, Jian,Terrett, Nicholas Kenneth,Shen, Jingkang
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p. 3090 - 3104
(2013/07/11)
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- Synthesis of polysubstituted olefins by Pd-catalyzed cross-coupling reaction of tosylhydrazones and aryl nonaflates
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Aryl nonaflates are employed as electrophiles in the Pd-catalyzed cross-coupling with tosylhydrazones affording di-, tri-, and tetrasubstituted olefins. Fine tunning of the reaction conditions are required to accomplish the coupling successfully, includin
- Barluenga, Jose,Florentino, Lucia,Aznar, Fernando,Valdes, Carlos
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supporting information; experimental part
p. 510 - 513
(2011/03/22)
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- ANTIMICROBIAL COMPOSITIONS AND METHODS OF USE
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The present invention is directed to compounds of formula I, pharmaceutical compositions comprising the compounds, and methods for making and using the inventive compounds.
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Page/Page column 26
(2008/12/07)
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- 2-Arylallyl as a new protecting group for amines, amides and alcohols
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Amines, amides and ethers containing 2-arylallyl groups are selectively and easily deprotected with tert-butyllithium. This transformation probably involves a carbolithiation reaction of the styrenyl moiety followed by a β-elimination process. The Royal Society of Chemistry 2005.
- Barluenga, Jose,Fananas, Francisco J.,Sanz, Roberto,Marcos, Cesar,Ignacio, Jose M.
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p. 933 - 935
(2007/10/03)
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- (2R)-2-Methylchromane-2-carboxylic acids: Discovery of selective PPARα agonists as hypolipidemic agents
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A SAR study was conducted on chromane-2-carboxylic acid toward selective PPARα agonisim. As a result, highly potent, and selective PPARα agonists were discovered. The optimized compound 43 exhibited robust lowering of total cholesterol levels in hamster and dog animal models.
- Koyama, Hiroo,Boueres, Julia K.,Miller, Daniel J.,Berger, Joel P.,MacNaul, Karen L.,Wang, Pei-Ran,Ippolito, Marc C.,Wright, Samuel D.,Agrawal, Arun K.,Moller, David E.,Sahoo, Soumya P.
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p. 3347 - 3351
(2007/10/03)
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- Kinetics of chlorination of phenol and monosubstituted phenols by t-butyl hypochlorite in aqueous alkaline medium
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The kinetics of chlorination of the parent and sixteen monosubstituted phenols (2-chloro, 2-methyl, 2-carboxy, 2-nitro, 3-chloro, 3-methyl, 3-carboxy, 4-fluoro, 4-chloro, 4-bromo, 4-methyl, 4-ethyl, 4-methoxy, 4-carboxy, 4-acetyl and 4-nitro) by t-BuOCl have been studied in aqueous alkaline medium. The rates of reactions show first order kinetics each in |t-BuOCl| and |XC 6H4OH| and inverse first order in |OH-|. Variation in either ionic strength or addition of reaction product has no significant effect on the rates of reactions, while lowering of the dielectric constant of the medium increases the rate. The rates are measured at different temperatures and the activation parameters for all the phenols computed. A mechanism involving the electrophilic attack of phenoxide ions by HOCl in the rate determining step is suggested. The rates decrease in the order: 3-CH 3 > 2-CH3 > 4-OCH3 > 4-CH3 > 4-C2H5 > H > 3-Cl > 3-COO- > 4-F > 2-COO- > 4-Br > 2-Cl > 4-Cl > 4-COO- > 4-COCH3 > 2-NO2 > 4-NO2. Hammett equation of the type, log k = -3.44 - 2.35 ρ is found to be valid for substituent effects. The enthalpy and entropy of activation are correlated.
- Moodithaya,Gowda, B. Thimme
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p. 420 - 425
(2007/10/03)
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- Highly Selective Aromatic Chlorinations. Part 2. The Chlorination of Substituted Phenols, Anisoles, Anilines, and Related Compounds with N-Chloroamines in Acidic Solution
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Phenols, anisoles, anilines, and related compounds are chlorinated in trifluoroacetic acid at room temperature by N-chlorodialkylamines and N-chlorotrialkylammonium salts.With monsubstituted compounds and their 2- and 3-substituted derivatives the reaction occurs efficiently and selectively at the 4-position.The reactivity of these substrates and the selectivity of their chlorinations are determined by electronic rather than steric effects of the substituent.Blocking the reaction with a substituent at the 4-position generally leads to only poor or moderate yields of the 2-chlorinated product.Evidence for radical and cation radical intermediates has been obtained in the reactions of some of the 4-substituted reactants and the mechanism of chlorination is discussed in the light of these findings.The reactions of selected substrates have been scaled up to give laboratory syntheses.
- Smith, John R. Lindsay,McKeer, Linda C.,Taylor, Jonathan M.
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p. 385 - 392
(2007/10/02)
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- Halogenation regioselective en serie aromatique. III. Influence des interactions donneur-accepteur au cours de la chloration des noyaux aromatiques par les hexachlorocyclohexadienones
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The perchlorocyclohexadienones reagents "o" and "p" selectively chlorinate aromatic rings.The magnitude of the association constants of these reagents with alkylphenols and the kinetics of the chlorination of 4-methoxyphenol by reagent "o" show the import
- Lemaire, Marc,Guy, Alain,Guette, Jean-Paul
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p. 477 - 484
(2007/10/02)
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- Regiospecific Chlorination of Aromatic Substrates using Donor-Acceptor and Hydrogen Bonding Interactions
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The chlorination of aromatic substances has been achieved with good regioselectivity using 2,3,4,4,5,6-hexachlorocyclohexa-2,5-dien-1-one and 2,3,4,5,6,6-hexachlorocyclohexa-2,4-dien-1-one as chlorinating agents.
- Guy, Alain,Lemaire, Marc,Guette, Jean-Paul
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