- Electrochemical Nitration with Nitrite
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Aromatic nitration has tremendous importance in organic chemistry as nitroaromatic compounds serve as versatile building blocks. This study represents the electrochemical aromatic nitration with NBu4NO2, which serves a dual role as supporting electrolyte and as a safe, readily available, and easy-to-handle nitro source. Stoichiometric amounts of 1,1,1-3,3,3-hexafluoroisopropan-2-ol (HFIP) in MeCN significantly increase the yield by solvent control. The reaction mechanism is based on electrochemical oxidation of nitrite to NO2, which initiates the nitration reaction in a divided electrolysis cell with inexpensive graphite electrodes. Overall, the reaction is demonstrated for 20 examples with yields of up to 88 %. Scalability is demonstrated by a 13-fold scale-up.
- Blum, Stephan P.,Nickel, Christean,Sch?ffer, Lukas,Karakaya, Tarik,Waldvogel, Siegfried R.
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p. 4936 - 4940
(2021/10/25)
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- N-Nitroheterocycles: Bench-Stable Organic Reagents for Catalytic Ipso-Nitration of Aryl- And Heteroarylboronic Acids
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Photocatalytic and metal-free protocols to access various aromatic and heteroaromatic nitro compounds through ipso-nitration of readily available boronic acid derivatives were developed using non-metal-based, bench-stable, and recyclable nitrating reagents. These methods are operationally simple, mild, regioselective, and possess excellent functional group compatibility, delivering desired products in up to 99% yield.
- Budinská, Alena,Katayev, Dmitry,Passera, Alessandro,Zhang, Kun
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supporting information
(2020/03/30)
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- Regioselective Functionalization of 9,9-Dimethyl-9-silafluorenes by Borylation, Bromination, and Nitration
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Despite the utility of 9-silafluorenes as functional materials and as building blocks, methods for efficient functionalization of their backbone are rare, probably because of the presence of easily cleavable C-Si bonds. Although controlling the regioselectivity of iridium-catalyzed direct borylation of C-H bonds is difficult, we found that bromination and nitration of 2-methoxy-9-silafluorene under mild conditions occurred predominantly at the electron-rich position. The resulting product having methoxy and bromo groups can be utilized as a building block for the synthesis of unsymmetrically substituted 9-silafluorene-containing π-conjugated molecules.
- Murai, Masahito,Nishinaka, Naoki,Kimura, Mizuki,Takai, Kazuhiko
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- Regioselective Functionalization of 9,9-Dimethyl-9-silafluorenes by Borylation, Bromination, and Nitration
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Despite the utility of 9-silafluorenes as functional materials and as building blocks, methods for efficient functionalization of their backbone are rare, probably because of the presence of easily cleavable C-Si bonds. Although controlling the regioselectivity of iridium-catalyzed direct borylation of C-H bonds is difficult, we found that bromination and nitration of 2-methoxy-9-silafluorene under mild conditions occurred predominantly at the electron-rich position. The resulting product having methoxy and bromo groups can be utilized as a building block for the synthesis of unsymmetrically substituted 9-silafluorene-containing ?-conjugated molecules.
- Murai, Masahito,Nishinaka, Naoki,Kimura, Mizuki,Takai, Kazuhiko
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p. 5667 - 5676
(2019/05/10)
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- Method of using I2O5/NaNO2 to nitrify electron-rich aromatic compounds
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The invention belongs to the field of organic chemical medicine, and especially relates to a method of using I2O5/NaNO2 to nitrify electron-rich aromatic compounds. According to the method, electron-rich aromatic compounds are taken as the raw material; sodium nitrite is taken as a nitrifying agent; at the same time, iodine pentoxide is added and taken as an oxidizing agent; then a proper amount of a solvent is added to carry out reactions for a while at a temperature of 10 to 25 DEG C under stirring; after reactions, a sodium thiosulfate solution is added to quench the reactions; the reactionsystem is extracted for three times by ethyl acetate; then the organic phases are merged and dried by anhydrous sodium sulfate; filtering is carried out, the solvent is evaporated maximally; silica gel is used to carry out adsorption, and the target product is obtained through column chromatography separation. The goal of converting electron-rich aromatic compounds into corresponding nitrification products under mild conditions is realized.
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Paragraph 0029; 0003
(2019/10/02)
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- Direct nitration method of electron-enriched aromatic hydrocarbons
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The invention discloses a direct nitration method of electron-enriched aromatic hydrocarbons, and belongs to the field of organic synthesis. The direct nitration method is a novel green free radical nitration method; aromatic hydrocarbons are taken as raw materials, acetonitrile, dichloromethane, chloroform, or acetone is taken as a reaction solvent, at room temperature conditions, the raw materials and green nitration reagent tert-butyl nitrite (TBN) are subjected to free radical nitration so as to obtain nitro-aromatic compounds. According to the direct nitration method, no metal is adoptedin reaction, tert-butyl nitrite is directly adopted in nitration reaction. Electron-donating groups such as OMe are introduced, the electron density of aromatic compounds is increased, the nitration reaction possibility is increased. The using amount of tert-butyl nitrite is reduced; only a product and tert-butyl alcohol are generated, environment pollution is reduced. The direct nitration methodis promising in application prospect in the field of nitro-aromatic compound synthesis, green nitration is realized, and a novel idea is provided for large-scale industrialized nitro-aromatic compoundproduction.
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Paragraph 0072-0074
(2018/10/02)
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- Class of large ring heterocyclic compound restraining HCV and manufacturing and uses thereof
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The invention relates to a class of compounds that inhibit HCV. The compounds are represented by Formula A. The invention also relates to preparation and pharmaceutical use of the compounds.
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Paragraph 0271-0274
(2017/09/01)
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- Nucleophilic Nitration of Arynes by Sodium Nitrite and its Multicomponent Reaction Leading to Double-Functionalized Arenes
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An unusual nucleophilic nitration of arynes by NaNO2 in the presence of water has been developed, and the concept was further demonstrated to accomplish a double functionalization of arynes using a multicomponent reaction protocol to synthesize pharmaceutically important (2-nitrophenyl)methanol derivatives. Such substitution ortho to -NO2 is difficult by other means. The reaction conditions are mild and avoid the use of strong acids, expensive transition metal catalysts, and additives.
- Dhokale, Ranjeet A.,Mhaske, Santosh B.
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supporting information
p. 3010 - 3013
(2016/07/06)
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- 3,4-methylenedioxy aniline preparation method
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A 3,4-methylenedioxy aniline preparation method applied to the field of chemosynthesis comprises the following steps: (1) adding dilute nitric acid into a reaction vessel for heating; (2) dropwise adding 1,2-methylenedioxy benzene into the reaction vessel slowly, carrying out intense stirring during the dropwise adding, and carrying out heat preservation after the dropwise adding is finished; (3) carrying out cooling and filtration to obtain a wet product of 3,4-methylenedioxy nitrobenzene, carrying out washing with purified water till the pH value of the wet product reaches 7, and carrying out vacuum drying to obtain 3,4-methylenedioxy nitrobenzene; (4) putting 3,4-methylenedioxy nitrobenzene, a nickel catalyst and one or more reaction solvents into a high-pressure reaction kettle for heating, injecting hydrogen, filtering out the nickel catalyst after the reaction is finished, carrying out high vacuum distillation after a low-boiling-point substance is removed through reduced pressure distillation, and collecting fractions to obtain 3,4-methylenedioxy aniline. The 3,4-methylenedioxy aniline preparation method has the advantages that nitrification reduction and hydrogenation reduction processes are adopted; less waste water, waste gas and solid waste are treated; the selectivity is high; the product treatment is easy; the product yield and the product quality are high; nitric acid, the hydrogenation catalyst and the hydrogenation organic solvents can be recovered for direct application.
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Paragraph 0010; 0011
(2016/11/14)
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- Molecular modeling and snake venom phospholipase A2 inhibition by phenolic compounds: Structure-activity relationship
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In our earlier study, we have reported that a phenolic compound 2-hydroxy-4-methoxybenzaldehyde from Janakia arayalpatra root extract was active against Viper and Cobra envenomations. Based on the structure of this natural product, libraries of synthetic structurally variant phenolic compounds were studied through molecular docking on the venom protein. To validate the activity of eight selected compounds, we have tested them in in vivo and in vitro models. The compound 21 (2-hydroxy-3-methoxy benzaldehyde), 22 (2-hydroxy-4-methoxybenzaldehyde) and 35 (2-hydroxy-3-methoxybenzylalcohol) were found to be active against venom-induced pathophysiological changes. The compounds 20, 15 and 35 displayed maximum anti-hemorrhagic, anti-lethal and PLA2 inhibitory activity respectively. In terms of SAR, the presence of a formyl group in conjunction with a phenolic group was seen as a significant contributor towards increasing the antivenom activity. The above observations confirmed the anti-venom activity of the phenolic compounds which needs to be further investigated for the development of new anti-snake venom leads.
- Alam, Md. Iqbal,Alam, Mohammed A.,Alam, Ozair,Nargotra, Amit,Taneja, Subhash Chandra,Koul, Surrinder
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p. 209 - 219
(2016/03/22)
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- Quinoxalin -2 (1H)-ketone compound and its preparation method and application
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The invention relates to a 1-substituted-6-methoxy-7-(3-morpholine propoxy) quinoxaline-2(1H)-ketone compound which is shown as the formula (I), preparation method and an application thereof. The benzodioxole is used as the raw material and subjected to nitration reaction for two times to produce the dinitration product: 5,6-dinitrobenzo[d][1,3] dioxacyclopentane, the 5,6-dinitrobenzo[d][1,3] dioxacyclopentane is subjected to ring opening under conditions of strong alkaline to obtain the ring opening product: 2-methoxy-4,5-dinitrophenol, the 2-methoxy-4,5-dinitrophenol and 4-(3-chloropropyl) morpholine are allowed to perform nucleophilic substitution, so as to obtain 4-(3-(2- methoxy-4,5-dinitrophenoxy) propyl) morpholine, the 4-(3-(2- methoxy-4,5-dinitrophenoxy) propyl) morpholine is reduced and allowed to perform ring closing reaction with ethyl glyoxalate to produce 6-methoxy-7-(3-morpholine propoxy) quinoxaline-2(1H)-ketone, and finally the 6-methoxy-7-(3-morpholine propoxy) quinoxaline-2(1H)-ketone is allowed to react with halogenated hydrocarbon containing substituents R under the alkaline condition, so as to produce the 1-substituted-6-methoxy-7-(3-morpholine propoxy) quinoxaline-2(1H)-ketone compound. The ketone compound has inhibition effect on EGFR kinase.(img file='DDA0000468270950000011.TIF' wi='928' he='416'/).
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Page/Page column 2; 5; 7
(2016/10/10)
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- Catalyst-free ipso-nitration of aryl boronic acids using bismuth nitrate
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We report a catalyst-free ipso-nitration of aryl boronic acids using bismuth (III) nitrate as nitrating agent. Reaction proceeds in shorter reaction times with moderate to excellent yields. This method is operationally simple, regioselective, and possesses excellent functional group compatibility to synthesize nitroarenes.
- Yadav, Rammohan R.,Vishwakarma, Ram A.,Bharate, Sandip B.
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supporting information
p. 5958 - 5960,3
(2020/07/31)
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- Pd-catalyzed conversion of aryl chlorides, triflates, and nonaflates to nitroaromatics
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(Chemical Equation Presented) An efficient Pd catalyst for the transformation of aryl chlorides, triflates, and nonaflates to nitroaromatics has been developed. This reaction proceeds under weakly basic conditions and displays a broad scope and excellent
- Fors, Brett P.,Buchwald, Stephen L.
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supporting information; experimental part
p. 12898 - 12899
(2009/12/07)
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- FUSED AMINO PYRIDINE AS HSP90 INHIBITORS
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The present invention relates to HSP90 inhibitors containing fused amino pyridine core that are useful as inhibitors of HSP90 and their use in the treatment of HSP90 related diseases and disorders such as cancer, an autoimmune disease, or a neurodegenerative disease.
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Page/Page column 58
(2008/12/08)
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- A new method of bromination of aromatic rings by an iso-amyl nitrite/HBr system
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A mixture of iso-amyl nitrite/HBr is shown to be a mild and efficient reagent for electrophilic aromatic bromination. The reaction succeeds with slightly activated arenes and heterocyclic compounds. By using HCl instead of HBr, chlorination can also be performed in few cases. The i-amONO2/HBr mixture can also be utilized for bromination in the α-position of electron withdrawing groups. A possible mechanism is briefly discussed.
- Gavara, Laurent,Boisse, Thomas,Rigo, Beno?t,Hénichart, Jean-Pierre
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p. 4999 - 5004
(2008/09/21)
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- The efficiency of light-directed synthesis of DNA arrays on glass substrates
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New methods based on photolithography and surface fluorescence were used to determine photodeprotection rates and stepwise yields for light-directed oligonucleotide synthesis using photolabile 5'-(((α-methyl-2- nitropiperonyl)-oxy)carbonyl)(MeNPOC)-2'-deoxynucleoside phosphoramidites on planar glass substrates. Under near-UV illumination (primarily 365 nm) from a mercury light source, the rate of photoremoval of the MeNPOC protecting group was found to be independent of both the nucleotide and length of the growing oligomer (t( 1/4 ) = 12 s at 27.5 mW/cm2). A moderate dependence on solvent polarity was observed, with photolysis proceeding most rapidly in the presence of nonpolar solvents or in the absence of solvent (e.g., t( 1/4 ) = 10 - 13 s at 27.5 mW/cm2). In solution, the photolysis rate was linearly dependent on light intensity over the range 5-50 mW/cm2. Average stepwise yields for the synthesis of dodecamer oligonucleotides were in the range of 92-94%, using monomers based on N6-(phenoxyacetyl)-2'-deoxyadenosine, N2- isobutyryl-2'-deoxyguanosine, N4-isobutyryl-2'-deoxycytidine, and thymidine. By comparison, an efficiency of 98%/step was obtained using a conventional 5'-dimethoxytrityl monomer with acid deprotection on the same support. The lower yields associated with the photochemical process appears to be due to incomplete recovery of free 5'-hydroxyl groups after photolysis on the support, although high yields of 5'-OH nucleosides (≤96%) are consistently observed when 5'-MeNPOC monomers are photolyzed in solution.
- McGall, Glenn H.,Barone, Anthony D.,Diggelmann, Martin,Fodor, Stephen P. A.,Gentalen, Erik,Ngo, Nam
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p. 5081 - 5090
(2007/10/03)
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- Thermal and photochemical decomposition pathways of trinitromethylarenes. part II. The effects of ethanol on the photolysis reactions of some alkoxy- and dialkoxyarenes in the presence of tetranitromethane. enhancement of adduct and trinitromethyl substitution product formation
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The photolysis of the charge transfer (CT) complex of tetranitromethane with 1-methoxynaphthalene, 1,4-dimethoxybenzene, 1,2-dimethoxybenzene, 1,2-methylenedioxybenzene or 2-methylanisole is reported for dichloromethane, acetonitrile, dichloromethane-ethanol and acetonitrile-ethanol solvent systems. The effects of adding ethanol (8% v/v ? 1.4 mol dm-3) to dichloromethane or acetonitrile as reaction solvents include: (i) the stabilization of alkoxytrinitro-methylarenes, thus reducing their normal tendency for decomposition according to ArC (NO2)3→ArCOOH→ArNO2, (ii) a reduction in the nucleophilicity of trinitromethanide ion, and (iii) changes in the regioselectivity of trinitromethanide ion attack on the radical cations of alkoxyaromatic compounds away from attack ipso to the alkoxy substituent. Adducts are also stabilized, as shown by the photolysis of the CT complex of 1,4-dimethoxybenzene-tetranitromethane in dichloromethane-ethanol (8% v/v) which gives the epimeric 1,4-dimethoxy-3-nitro-6-trinitromethylcyclohexa-1,4-dienes and 1,4-dimethoxy-2-trinitromethylbenzene, in addition to 1,4-dimethoxy-2-nitrobenzene. The adducts are detected also among the products of photolysis reactions in neat dichloromethane or acetonitrile. Acta Chemica Scandinavica 1997.
- Butts, Craig P.,Eberson, Lennart,Hartshorn, Michael P.,Persson, Ola
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p. 718 - 732
(2007/10/03)
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- Zirconium-catalysed Oxidation of Primary Aromatic Amines to Nitro Compounds Using tert-Butylhydroperoxide
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A broad range of primary aromatic amines (1a-x) with electron donating and accepting substituents are oxidized in good to excellent yields to the nitro compounds 3a-x using tert-butylhydroperoxide as the oxidant and Zr(OtBu)4 as the catalyst. The corresponding nitroso compounds 2m,-2n, 2s and 2u can be isolated in the conversion of electron-rich anilines 1m, 1n, 1s and 1u. The aminopyridines 5a-d are also converted to the corresponding nitropyridines 6a-d, but in lower yields (41-47%).
- Krohn, Karsten,Kuepke, Jochen,Rieger, Hagen
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p. 335 - 339
(2007/10/03)
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- THE ESR SPECTRA, STRUCTURE, AND REACTIVITY OF AROMATIC RADICAL-CATIONS IN SUPERACIDS
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The oxidation of aromatic compounds by lead dioxide in superacids based on fluorosulfonic acid at -75 deg C takes place by a one-electron mechanism and leads in many cases to relatively stable radical-cations.The ESR spectra, the isotropic hyperfine coupling constants, data on the reactivity of the radical-cations, and the structures of the final products from their transformations under "long-life" conditions are presented.
- Rudenko, A. P.
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p. 1946 - 1980
(2007/10/03)
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- Influence of the Heterocyclic Side Ring on Orientation During Nitrations of 1,2-Alkylenedioxy-annelated Benzenes and Their Mononitro Derivatives
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Nitration of 1,2-alkylenedioxybenzenes 1 furnished the respective nitro derivatives 3 and 4 in the relative ratios: 4a:3a/100:trace, 4b:3b/98:2.4, 4c:3c/86:14, 4e:3e/91:9, 4f:3f/99:1.3.Nitration of 4 gave 5a:6a:8a/0:0:100, 5b:6b:8b/7.7:3.2:89, 5c:6c:8c/23:12:65, 5d:6d:8d/14:74:12, 5e:6e:8e/27:18:55 and 5f:6f:8f/23:7.0:70.Nitration of the isomeric 3 afforded the dinitroproducts 5, 6 and 7 in the following relative ratios: 5a:6a:7a/92:8:0, 5b:6b:7b/80:20:0, 5c:6c:7c/69:20:11, 5d:6d:7d/45:19:36, 5e:6e:7e/37:57:5.9 and 5f:6f:7f/64:36:0.Nitration of 3-nitro-1,2-dimethoxybenzene (9) furnished: 10:11/63:37.Orientation as a function of the h eterocyclic ring-size is discussed.
- Takakis, Ioannis M.,Hadjimihalakis, Phaedon M.
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p. 625 - 634
(2007/10/02)
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- THE OXIDATION OF AROMATIC AMINES IN THE PRESENCE OF "ELECTRON-RICH" AROMATIC SYSTEMS
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The oxidation of aromatic amines to the corresponding nitro substituents is performed under mild, nonacidic conditions in the presence of highly nucleophilic aromatic systems such as indoles and furans.
- Zabrowsky, Daniel L.,Moormann, Alan E.,Beck, Kenneth R.
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p. 4501 - 4504
(2007/10/02)
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- ELECTROCHEMICAL OXIDATION OF ORGANIC COMPOUNDS IN FLUOROSULFONIC ACID. IX. VOLTAMMETRIC CHARACTERISTICS OF THE OXIDATION OF SUBSTITUTED PHENOLS, THEIR DERIVATIVES, AND HETEROCYCLIC COMPOUNDS IN FLUOROSULFONIC ACID AND ACETONITRILE
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The electrochemical oxidation of phenols and their alkyl ethers not containing strong electron-withdrawing substituents in fluorosulfonic acid takes place in the form of the benzenonium ions and is irreversible in character.With the introduction of substituents of the -M type into the benzene ring the oxidation process affects the unprotonated molecules to a first approximation and in many cases goes reversibly to the radical-cations.Comparison of the oxidation potentials of the substrates in acetonitrile and fluorosulfonic acid made it possible to reveal certain characteristics of the fine structure of these radical-cations, which is determined by the ability of the latter to interact with the medium.Heterocyclic cations whose oxidation potentials in acetonitrile lie beyond the limit of the discharge of the supporting electrolyte can be oxidized in fluorosulfonic acid.Cations of the quinolinium, isoquinolinium, acridinium, acridizinium, imidazolium, and other series, which have irreversible many-electron waves in acetonitrile, give well-defined reversible peaks for oxidation to the corresponding radical-dications in fluorosulfonic acid.In phenyl- and benzyl-substituted cations the substituents and not the positively charged heterocycle itself can undergo oxidation.
- Rudenko, A. P.,Zarubin, M. Ya.,Pragst, F.
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p. 2145 - 2165
(2007/10/02)
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- Imidazole derivatives
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Tricyclic imidazole derivatives of the formula STR1 wherein R1 is 2-pyridyl optionally substituted by lower alkyl or lower alkoxy, n is the integer 0 or 1, R2 is hydrogen or lower alkyl, R3 and R4, independently, are hydrogen or lower alkyl, A is a group of the formula STR2 m is the integer 2 or 3, R5, R6, R7 and R8, independently, are hydrogen or lower alkyl, and R9 is hydrogen and R10 is hydrogen or lower alkyl or R9 and R10 taken together are oxo, provided that at least one of R3 and R4 is lower alkyl when A is a group of the formula and their pharmaceutically acceptable acid addition salts. The compounds of formula I inhibit gastric acid secretion and prevent the formation of gastric ulcers.
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- The Constituents of Schizandra chinensis BAILL. IX. The Cleavage of the Methylenedioxyl Moiety with Lead Tetraacetate in Benzene, and the Structure of Angeloylgomisin Q
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A procedure for selective cleavage of the methylenedioxyl moiety with lead tetraacetate in dry benzene is described.Piperonylic acid methyl ester (5), 4-nitro-1,2-methylenedioxybenzene (6), 3,4-methylenedioxytoluene (7), 2,3-methylenedioxyanisole (8) and gomisin A (9) afforded protocatechuic acid (12), 4-nitrocatechol (13), 3,4-dihydroxytoluene(14), 2,3-dihydroxyanisole (15) and compound 16, respectively.The structure of angeloylgomisin Q isolated from the fruits of Schizandra chinensis BAILL. (Schizandraceae), was elucidated as 1 by using the above reaction.Keywords--cleavage of methylenedioxyl moiety; lead tetraacetate; Schizandra chinensis BAILL.; Schizandraceae; dibenzocyclooctadiene; lignan; angeloylgomisin Q
- Ikeya, Yukinobu,Taguchi, Heihachiro,Yoshioka, Itiro
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p. 2893 - 2898
(2007/10/02)
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