- Preparation method of 2-bromo-1, 3-dimethoxybenzene
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The invention discloses a preparation method of 2-bromo-1, 3-dimethoxybenzene. The preparation method comprises the following steps: using tetrahydrofuran as a solvent, adding m-dimethoxybenzene, stirring to dissolve, cooling to 5-10 DEG C, slowly dropwis
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Paragraph 0003; 0022-0033
(2020/07/02)
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- Orthogonal Stability and Reactivity of Aryl Germanes Enables Rapid and Selective (Multi)Halogenations
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While halogenation is of key importance in synthesis and radioimaging, the currently available repertoire is largely designed to introduce a single halogen per molecule. This report makes the selective introduction of several different halogens accessible. Showcased here is the privileged stability of nontoxic aryl germanes under harsh fluorination conditions (that allow selective fluorination in their presence), while displaying superior reactivity and functional-group tolerance in electrophilic iodinations and brominations, outcompeting silanes or boronic esters under rapid and additive-free conditions. Mechanistic experiments and computational studies suggest a concerted electrophilic aromatic substitution as the underlying mechanism.
- Deckers, Kristina,Fricke, Christoph,Schoenebeck, Franziska
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supporting information
p. 18717 - 18722
(2020/08/25)
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- Decarboxylative Suzuki-Miyaura coupling of (hetero)aromatic carboxylic acids using iodine as the terminal oxidant
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A novel methodology for the decarboxylative Suzuki-Miyaura-type coupling has been established. This process uses iodine or a bromine source as both the decarboxylation mediator and the terminal oxidant, thus avoiding the need for stoichiometric amounts of transition metal salts previously required. Our new protocol allows for the construction of valuable biaryl architectures through the coupling of (hetero)aromatic carboxylic acids with arylboronic acids. The scope of this decarboxylative Suzuki reaction has been greatly diversified, allowing for previously inaccessible non-ortho-substituted aromatic acids to undergo this transformation. The procedure also benefits from low catalyst loadings and the absence of stoichiometric transition metal additives.
- Quibell, Jacob M.,Duan, Guojian,Perry, Gregory J.P.,Larrosa, Igor
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supporting information
p. 6445 - 6448
(2019/06/07)
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- Transition-metal-free decarboxylative bromination of aromatic carboxylic acids
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Methods for the conversion of aliphatic acids to alkyl halides have progressed significantly over the past century, however, the analogous decarboxylative bromination of aromatic acids has remained a longstanding challenge. The development of efficient methods for the synthesis of aryl bromides is of great importance as they are versatile reagents in synthesis and are present in many functional molecules. Herein we report a transition metal-free decarboxylative bromination of aromatic acids. The reaction is applicable to many electron-rich aromatic and heteroaromatic acids which have previously proved poor substrates for Hunsdiecker-type reactions. In addition, our preliminary mechanistic study suggests that radical intermediates are not involved in this reaction, which is in contrast to classical Hunsdiecker-type reactivity. Overall, the process demonstrates a useful method for producing valuable reagents from inexpensive and abundant starting materials.
- Quibell, Jacob M.,Perry, Gregory J. P.,Cannas, Diego M.,Larrosa, Igor
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p. 3860 - 3865
(2018/04/26)
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- COMPOUND AND ORGANIC LIGHT-EMITTING DEVICE INCLUDING THE SAME
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When a decrease in low-grey level region (e.g., 0 to 80 grey) efficiencies of organic light emitting devices is not constant, deviation among display panels may cause color change and stain in the low luminance region. Aspects of the present disclosure ar
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Paragraph 0260
(2017/03/21)
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- Decarboxylative Halogenation and Cyanation of Electron-Deficient Aryl Carboxylic Acids via Cu Mediator as Well as Electron-Rich Ones through Pd Catalyst under Aerobic Conditions
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Simple strategies for decarboxylative functionalizations of electron-deficient benzoic acids via using Cu(I) as promoter and electron-rich ones by employing Pd(II) as catalyst under aerobic conditions have been established, which lead to smooth synthesis of aryl halides (-I, Br, and Cl) through the decarboxylative functionalization of benzoic acids with readily available halogen sources CuX (X = I, Br, Cl), and easy preparation of benzonitriles from decarboxylative cyanation of aryl carboxylic acids with nontoxic and low-cost K4Fe(CN)6 under an oxygen atmosphere for the first time.
- Fu, Zhengjiang,Li, Zhaojie,Song, Yuanyuan,Yang, Ruchun,Liu, Yanzhu,Cai, Hu
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p. 2794 - 2803
(2016/04/26)
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- HETEROCYCLIC COMPOUND, MATERIAL FOR ORGANIC ELECTROLUMINESCENT ELEMENT PREPARED USING THE SAME, AND ORGANIC ELECTROLUMINESCENT ELEMENT AND ELECTRONIC APPARATUS PREPARED USING THE SAME
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PROBLEM TO BE SOLVED: To provide a novel material useful as an organic electroluminescent element material. SOLUTION: This invention relates to a heterocyclic compound wherein three five-membered rings are condensed on a benzene ring, and further, saturat
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Paragraph 0234; 0236
(2016/10/10)
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- Pd(II)-catalyzed bromo- and chlorodecarboxylation of electron-rich arenecarboxylic acids
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A bromo- and chlorodecarboxylation of various aromatic carboxylic acids catalyzed by Pd(II) has been developed in this work. A series of electron-rich arenecarboxylic acids gave the corresponding decarboxylative monohalogenation products under the typical reaction conditions.
- Peng, Xuefeng,Shao, Xiang-Feng,Liu, Zhong-Quan
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supporting information
p. 3079 - 3081
(2013/07/11)
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- Halodeboronation of organotrifluoroborates using tetrabutylammonium tribromide or cesium triiodide
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Halodeboronation of organotrifluoroborates using commercially available tetrabutylammonium tribromide (TBATB) or cesium triiodide in aqueous medium is reported. The mild, transition metal-free method has proven to be tolerant of a wide range of functional groups. High regio- and chemoselectivity are observed. Two synthetic routes to (Z)-dibromoalkenes from alkynes, through stereodefined (Z)-2-bromoalkenyltrifluoroborates and (Z)-1,2-bis(boryl) alkenyltrifluoroborates, have been developed using the TBATB mediated bromodeboronation as the key step.
- Yao, Min-Liang,Kabalka, George W.,Blevins, David W.,Reddy, Marepally Srinivasa,Yong, Li
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experimental part
p. 3738 - 3743
(2012/06/30)
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- ANTHRACENE DERIVATIVE AND ORGANIC ELECTROLUMINESCENT ELEMENT USING THE SAME
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An anthracene derivative represented by the following formula (1): In the formula (1), Z is a structure represented by the following formula (2). In the formula (2), at least one pair of adjacent two substituents of R11 to R18 form a ring represented by the following formula (3) or (4):
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Page/Page column 46
(2012/04/17)
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- Regioselectivity in the aryne cross-coupling of aryllithiums with functionalized 1,2-dibromobenzenes
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Tri- and tetrasubstituted ortho-bromobiaryls have been synthesized in good-to-excellent yields by aryne cross-coupling reactions starting from 1,3-dimethoxybenzene and functionalized 1,2-dibromobenzenes. This study outlines the influence of the 1,2-dibromobenzene precursor as well as the reaction temperature on the outcome of the aryl-aryl bond formation and indicates, in the case of dissymmetrical benzyne precursors, how structural parameters (electronic effects, steric hindrance, temperature, etc.) control the regioselectivity of the aryne cross-coupling reactions. A wide range of o,o′-tri- and-tetrasubstituted biphenyls have been prepared by a transition-metal-free "aryne" cross-coupling starting from 2,6-dimethoxyphenyllithium and various functionalized 1,2-dibromobenzenes. Mechanistic investigations outline the key parameters that govern both the aryl-aryl bond formation and the regioselectivity of the reaction with dissymmetrical aryne precursors. Copyright
- Diemer, Vincent,Begaud, Manon,Leroux, Frederic R.,Colobert, Fracoise
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scheme or table
p. 341 - 354
(2011/02/28)
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- Enantioselective synthesis of (+)-estrone exploiting a hydrogen bond-promoted Diels?Alder reaction
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Starting from Danes diene and methylcyclopentenedione, (+)-estrone is synthesized along the Quinkert?Dane route in 24% total yield. The key step is an enantioselective Diels?Alder reaction promoted by an amidinium catalyst as efficiently as by a traditional Ti-TADDOLate Lewis acid.
- Weimar, Marko,Duerner, Gerd,Bats, Jan W.,Goebel, Michael W.
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supporting information; experimental part
p. 2718 - 2721
(2010/07/17)
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- N-salicylideneanilines: Tautomers for formation of hydrogen-bonded capsules, clefts, and chains
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The synthesis, characterization, and solid-state structures of new salicylaldimines are reported. Bis(N-salicylideneaniline)s (BSANs) and tris(N-salicylideneaniline)s (TSANs) are sterically encumbered compounds featuring a central six-membered ring in the
- Sauer, Marc,Yeung, Charles,Chong, Jonathan H.,Patrick, Brian O.,MacLachlan, Mark J.
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p. 775 - 788
(2007/10/03)
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- The conversion of phenols to the corresponding aryl halides under mild conditions
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Mild, novel procedures have been developed for the syntheses of aryl halides from the corresponding phenols in modest to good yields via boronate ester intermediates.
- Thompson, Alicia L. S.,Kabalka, George W.,Akula, Murthy R.,Huffman, John W.
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p. 547 - 550
(2007/10/03)
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- Enantioposition-selective arylation of biaryl ditriflates by palladium- catalyzed asymmetric Grignard cross-coupling
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Asymmetric cross-coupling of achiral biaryl ditriflates with aryl Grignard reagents in the presence of 1 equiv of lithium bromide and 5 tool % of palladium complex PdCl2[(S)-alaphos], where alaphos stands for (2- dimethylamino)propyldiphenylphosphine, gave axially chiral monophenylation products with high enantioposition-selectivity. The remaining triflate group in the monophenylation products was substituted with carboxyl and diphenylphosphino groups through palladium-catalyzed carbonylation and diphenylphosphinylation, respectively.
- Kamikawa, Takashi,Hayashi, Tamio
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p. 3455 - 3466
(2007/10/03)
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- Optically active tertiary phosphine compound, transition metal complex comprising the same as ligand and process for preparing optically active organic silicon compound using said transition metal complex
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A tertiary phosphine compound of the formula (1): STR1 in which R1 and R1' are hydrogen atoms or together form --CH=CH--CH=CH--; R2 and R3 together form a group of the formula (a): STR2 in which --.circle-solid. represent a bond to be bonded to the R3 group, and --? represents a bond to be bonded to the R2 group when R1 and R1 ' together form --CH=CH--CH=CH--, or when R1 is a hydrogen atom, R2 and R3 together form --CH=CH--CH=CH-- or R2 is a hydrogen atom and R3 is a substituted or unsubstituted alkyl group, or a substituted or unsubstituted phenyl group; A1 is a 3-trifluoromethylphenyl group or a 3,5-bis(trifluoromethyl)phenyl group when R1 is a hydrogen atom and R2 and R3 together form --CH=CH--CH=CH--, or a substituted or unsubstituted phenyl group when R1 is not a hydrogen atom or when R2 and R3 do not together form --CH=CH--CH=CH--.
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- Catalytic Halogenation of Selected Organic Compounds Mimicking Vanadate-dependent Marine Metalloenzymes
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The ammonium metavanadate, mimicking vanadate-dependent metalloenzymes, efficiently catalyses the halogenation of a variety of organic substrates in dilute conditions in moderate to good yields using dilute hydrogen peroxide (30percent) as an oxidizing agent exhibiting remarkable ortho selectivity with electron-rich aromatics.
- Dinesh, Chimmanamada U.,Kumar, Rajiv,Pandey, Bipin,Kumar, Pradeep
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p. 611 - 612
(2007/10/02)
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- Selective Preparation of 1-Halo-2,6-dimethoxybenzenes from Bis(2,6-dimethoxyphenyl)dimethyltin
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With a hope to explore a facile method for preparation of 1-halo-2,6-dimethoxybenzenes, bis(2,6-dimethoxyphenyl)dimethyltin was prepared from 1,3-dimethoxybenzene, butyllithium, and dimethyltin dichloride or dimethyltin sulfide.The compound reacted with N
- Wada, Masanori,Wakamori, Hiroyuki,Hiraiwa, Akira,Erabi, Tatsuo
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p. 1389 - 1391
(2007/10/02)
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- 4. Synthese von Plectranthonen, diterpenoiden Phenanthren-1,4-chinonen
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The following phenanthrene-1,4-diones have been synthesized by using the photocyclization of the corresponding highly substituted stilbenes as the key step: 3-hydroxy-5,7,8-trimethyl-2-(prop-2-enyl)phenanthrene-1,4-dione (1), (RS)-, (R)-, and (S)-2--1-methylethyl)acetate (2, 31, and 32, resp.), 3-hydroxy-7,8-dimethyl-2-(prop-2-enyl)phenanthrene-1,4-dione (3), 3-hydroxy-7,8,10-trimethyl-2-(prop-2-enyl)phenanthrene-1,4-dione (4), 5,7,8-trimethyl-2-(prop-2-enyl)phenanthrene-1,4-dione (17) and 3-hydroxy-2-methylphenanthrene-1,4-dione (42).The quinones 1 and 3 proved to be identical with recently isolated plectranthons A and C.Compounds 2, 31, and 32 exhibited the same UV/VIS, IR, 1H-NMR and mass spectra as natural plectranthon B, but had different melting points.This might be due either to crystal modifications or to diastereoisomerism caused by the helical structure of the phenanthrene-1,4-dione skeleton.The spectral data of synthetic 4 were not compatible with those of natural plectranthon D for which structure 4 had been proposed based mainly on 1H-NMR arguments concerning the chemical shifts of H-C(9) and H-C(10) in 1-3.Extensive 1H-NMR investigations have now revealed that the currently stated assignments of the H-C(9)/H-C(10) AB system have to be reversed for highly substituted phenanthrene-1,4-diones: in the model compounds 2-methylphenanthrene-1,4-dione (41) and 2, H-C(10) resonates at lower field as expected (peri-position), whereas in the highly substituted congeners 1, 2, 3, 31, and 32, H-C(9) is shifted paramagnetically, a fact which had lead to the erroneous assignment of structure 4 for natural plectranthon D.
- Kaliakoudas, Dimitrios,Eugster, Conrad Hans,Rueedi, Peter
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- Regioselective Reductive Electrophilic Substitution of 1,2,3-Trimethoxybenzene and Its 5-Alkyl-Substituted Homologues
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The methoxy group in the 2-position of 1,2,3-trimethoxybenzene (1) can be regioselectively removed by electron transfer from alkali metals and replaced with a variety of electrophiles in a one-pot procedure, affording 2-substituted resorcinol dimethyl ethers.The usefulness of this synthetic method is illustrated by numerous examples.This reaction procedure has been successfully extended to the 5-methyl-substituted homologue (2), but limitations occur with the higher homologue 1-pentyl-3,4,5-trimethoxybenzene (3).Investigations on the mechanism of demethoxylation, with the aid of labeling experiments, provided clear evidence for the intermediacy of aryl radicals and explained the low yields obtained in the reductive electrophilic substitution of compound 3.
- Azzena, Ugo,Denurra, Teresa,Melloni, Giovanni,Piroddi, Anna Maria
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p. 5386 - 5390
(2007/10/02)
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- THE INVENTION OF RADICAL REACTIONS. PART XVI. RADICAL DECARBOXYLATIVE BROMINATION AND IODINATION OF AROMATIC ACIDS
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Thiohydroxamic esters of aromatic carboxylic acids undergo clean decarboxylative bromination or iodination on treatment with bromotrichloromethane, iodoform or diiodomethane in the presence of a radical initiator.
- Barton, Derek H.R.,Lacher, Brigitte,Zard, Samir Z.
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p. 4321 - 4328
(2007/10/02)
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- THE DECOMPOSITION OF SUBSTITUTED BENZOYL PEROXIDES IN THE PRESENCE OF DIMETHOXYBENZENES
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Benzoyl peroxides, particularly those containing electron withdrawing substituents, undergo rapid decomposition in the presence of m-dimethoxybenzene, p-dimethoxybenzene, 2,5-di-t-butyl-1,4-dimethoxybenzene, and 2,5-dimethyl-1,4-dimethoxybenzene.Reactions are first oder in peroxide and dimethoxy benzene, increasing in the order given.Identified products are the acids corresponding to the peroxide and esters involving ring substitution, ring substitution with elimination of a t-Bu group, and benzylic substitution.It is proposed that reaction involves a rate-determining charge transfer transition state leading to radical ion pairs which collapse to products.No free radicals have been detected.
- Walling, Cheves,Chengxue, Zhao
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p. 1105 - 1112
(2007/10/02)
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