- Eco-Friendly Methodology for the Formation of Aromatic Carbon–Heteroatom Bonds by Using Green Ionic Liquids
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A new sustainable method is reported for the formation of aromatic carbon–heteroatom bonds under solvent-free and mild conditions (no co-oxidant, no strong acid and no toxic reagents) by using a new type of green ionic liquid. The bromination of methoxy arenes was chosen as a model reaction. The reaction methodology is based on only using natural sodium bromine, which is transformed into an electrophilic brominating reagent within an ionic liquid, easily prepared from the melted salt FeCl3 hexahydrate. Bromination reactions with this in-situ-generated reagent gave good yields and excellent regioselectivity under simple and environmentally friendly conditions. To understand the unusual bromine polarity reversal of sodium bromine without any strong oxidant, the molecular structure of the reaction medium was characterised by Raman and direct infusion electrospray ionisation mass spectroscopy (ESI-MS). An extensive computational investigation using density functional theory methods was performed to describe a mechanism that suggests indirect oxidation of Br? through new iron adducts. The versatility of the methodology was successively applied to nitration and thiocyanation of methoxy arenes using KNO3 and KSCN in melted hexahydrated FeCl3.
- Richards, Kenza,Petit, Eddy,Legrand, Yves-Marie,Grison, Claude
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supporting information
p. 809 - 814
(2020/11/30)
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- Enantioselective Synthesis of (+)-Mitomycin K by a Palladium-Catalyzed Oxidative Tandem Cyclization
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The mitomycins, a family of bioactive natural products, feature a compact 6/5/5-fused polycyclic ring structure densely decorated with highly reactive and/or fragile quinone, amino ketal, and aziridine as well as carbamate moieties. It is this striking feature that has defeated numerous synthetic attempts towards these apparently small molecules, rendering them one of the most formidable targets for total synthesis. We herein report the first enantioselective synthesis of (+)-mitomycin K, a representative of G series mitomycins. The key step of this synthesis is an enantioselective oxidative cyclization catalyzed by a palladium/(+)-sparteine system that had previously been developed by our group. The robustness of this method bodes well for further applications in the asymmetric total synthesis of natural products, particularly those with characteristic 6/5/5-fused pyrroloindole skeletons.
- Gu, Qiang-Shuai,Yang, Dan
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supporting information
p. 5886 - 5889
(2017/05/12)
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- Triton B-mediated efficient and convenient alkoxylation of activated aryl and heteroaryl halides
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A simple and convenient one-pot synthesis of aryl alkyl ethers by the alkoxylation of aryl halides with alcohol in the presence of Triton B as a base is described. The procedure is applicable for a variety of aryl and heteroaryl halides, and yields are very good. The use of a nonmetallic base and solvent-free conditions are important features of the reaction. Copyright Taylor & Francis Group, LLC.
- Meshram,Goud, P. Ramesh,Reddy, B. Chennakesava,Kumar, D. Aravind
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experimental part
p. 2122 - 2129
(2010/08/13)
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- (AZA)INDOLE DERIVATIVE AND USE THEREOF FOR MEDICAL PURPOSES
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The present invention provides compounds useful as agents for the prevention or treatment of a disease associated with abnormal serum uric acid level which has a uricosuric activity or the like. The present invention relates to (aza)indole derivatives represented by the following general formula (I) having xanthine oxidase inhibitory activities and useful as agents for the prevention or treatment of a disease associated with abnormality of serum uric acid level, prodrugs thereof, or salts thereof. In the formula (I), T represents nitro or cyano and the like; ring J represents aryl or heteroaryl and the like; Q represents carboxy or 5-tetazolyl and the like; Y represents H, OH, NH2, halogen, nitro, alkyl, alkoxy and the like; X1, X2 and X3 independently represent CR2 or N; R1 and R2 independently represent halogen, cyano, haloalkyl, A-D-E-G, -N(-D-E-G)2 and the like, in the formula, A represents a single bond, O, S and the like; D and G independently represent optionally substituted alkylene, cycloalkylene, heterocycloalkylene, arylene, heteroarylene and the like; E represents a single bond, O, S, COO, SO2 and the like.
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Page/Page column 27
(2009/12/27)
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- Nitration of some aromatic compounds by sodium nitrate in the presence of benzyltriphenylphosphonium peroxodisulfate
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A simple, mild, and regioselective method for the nitration of some aromatic compounds using sodium nitrate in the presence of benzyltriphenylphosphonium peroxodisulfate in acetonitrile as solvent is reported. Mild reaction conditions and good to excellent yields of the products are the noteworthy advantages of the method. Copyright Taylor & Francis Group, LLC.
- Tajik, Hassan,Zolfigol, Mohammad Ali,Albadi, Jalal,Eslami, Ramin
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p. 2771 - 2776
(2008/02/12)
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- BENZOTRIAZEPINONE DERIVATIVES
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The present invention is concerned with benzotriazepinone derivatives, their intermediates, uses thereof and processes for their production. In particular, the present invention relates to parathyroid hormone (PTH) and parathyroid hormone related protein (PTHrp) receptor ligands, (PTH-I or PTH/PTHrp receptor ligands). The invention also relates to methods of preparing such ligands and to compounds which are useful as intermediates in such methods.
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Page/Page column 63
(2010/11/29)
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- 2- (4-0X0-4H-QUINAZ0LIN-3-YL) ACETAMIDES AND THEIR USE AS VASOPRESSIN V3 ANTAGONISTS
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The present invention relates to 2-(4-oxo4H-quinazolin-3-yl)acetamicle derivatives of formula (I), and to their use as vasopressin V3 antagonists, particularly for the treatment of depression.
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Page/Page column 33
(2010/11/23)
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- 1,2-disubstituted 1,4-dihydro-4-oxoquinoline compounds
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The present invention relates to substituted 1,4-dihydro-4-oxoquinolines having antiviral activity. The substituents are present at positions 1, 2 and at least one of 5-8 positions of the quinoline ring.
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- Photochemical nitration by tetranitromethane. Part XXXVII. Adduct formation and the regiochemistry of attack of trinitromethanide ion on radical cations in the photochemical reactions of 2-methyl-, 2,3-dimethyl- and 2,4-Dimethylanisoles
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The photolysis of the charge transfer (CT) complex of tetranitromethane and 2-methylanisole 2 in dichloromethane at 20 °C gives the epimeric 1-methoxy-6-methyl-6-nitro-3-trinitromethylcyclohexa-1,4-dienes 8 and 9 in addition to 2-methyl-4-trinitromethylanisole (3) and 2-methyl-4-nitroanisole (4). In acetonitrile the yields of compound 4 and adducts 8 and 9 are significantly higher. Similar reaction of 2,3-dimethylanisole (6) in dichloromethane gave nitro-trinitromethyl adducts 10 and 11, hydroxy-trinitromethyl adducts 12 and 13, 2,3-dimethyl-5-trinitromethylanisole (14), 4-methoxy-2,3-dimethylbenzonitrile N-oxide (15), 2,3-dimethyl-4-trinitromethylanisole (16), 2,3-dimethyl-4-nitroanisole (17), 2,3-dimethyl-4,6-dinitrophenol (18), 3-methoxy-4,5-dimethyl-benzoic acid (19) and the hydroxy dinitro compound (20). The photolysis of the CT complex of 2,4-dimethylanisole (7) with tetranitromethane in dichloromethane gave the epimeric 1-methoxy-4,6-dimethyl-6-nitro-3-trinitromethylcyclohexa-1,4-dienes 21 and 22, together with 4,6-dimethyl-3-trinitromethylanisole (23), 4,6-dimethyl-2-nitrophenol (24), 4,6-dimethyl-2-trinitromethylanisole (25), 4,6-dimethyl-3-nitroanisole (26), 4,6-dimethyl-2-nitroanisole (27) and 4,6-dimethyl-4-nitrocyclohexa-2,5-dienone (28). The modes of formation of the above products are discussed, including the effects of the reaction solvent on those processes. The X-ray crystal structure of 1-methoxy-2-methyl-c-6-nitro-r-3-trinitromethylcyclohexa-1,4-diene (9) is reported. Acta Chemica Scandinavica 1997.
- Butts, Craig P.,Eberson, Lennart,Hartshorn, Michael P.,Robinson, Ward T.,Timmerman-Vaughan, David J.
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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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- Transition metal-diene complexes in organic synthesis, Part 22. The iron-mediated quinone imine cyclization: A general route to 3-hydroxycarbazoles
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Electrophilic aromatic substitution of 4-methoxyarylamines 2 by the tricarbonyliron-complexed cyclohexadienylium cations 1 leading to the iron complexes 3 is described. Chemoselective oxidation of the arylamine moiety of the complexes 3 to the quinone imine and iron-mediated quinone imine cyclization using appropriate oxidizing reagents (activated manganese dioxide or thallium(III) trifluoroacetate) led to the tricarbonyliron-complexed 4b,8a-dihydrocarbazol-3-ones 5. Demetalation of 5 with trimethylamine N-oxide at room temperature occurred with concomitant aromatization of the organic ligand and provided a broad access to the 3-hydroxy-9H-carbazoles 7.
- Knolker,Bauermeister,Pannek,Wolpert
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p. 397 - 408
(2007/10/02)
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- Heteroacetic acid derivatives
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Disclosed are compounds of formula STR1 wherein R is hydroxy, esterified hydroxy or etherified hydroxy; R1 is halogen, trifluoromethyl or lower alkyl; R2 is halogen, trifluoromethyl or lower alkyl; R3 is halogen, trifluoromethyl, lower alkyl, aryl, aryl-lower alkyl, cycloalkyl or cycloalkyl-lower alkyl; or R3 is the radical STR2 wherein R8 is hydrogen, lower alkyl, aryl, cycloalkyl, aryl-lower alkyl or cycloalkyl-lower alkyl; R9 is hydroxy or acyloxy; R10 represents hydrogen or lower alkyl; or R9 and R10 together represent oxo; R4 is hydrogen, halogen, trifluoromethyl or lower alkyl; X is --NR7, S or O; W is O or S; R5 represents hydrogen, lower alkyl or aryl-lower alkyl;and R6 represents hydrogen; or R5 and R6 together represent oxo provided that X represents --NR7; R7 represents hydrogen or lower alkyl; Z represents carboxyl, carboxyl derivatized as a pharmaceutically acceptable ester or as a pharmaceutically acceptable amide; and pharmaceutically acceptable salts thereof; which are useful as hypocholesteremic agents.
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- Multinuclear Magnetic Resonance Spectroscopic and Semiempirical Molecular Orbital (AM1) Studies of Substituted Anisoles
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13C, 15N, and 17O NMR spectra have been recorded for 4-nitroanisole (1), its 2-methyl-, 2-chloro-, 2-bromo-, 2-iodo-, 2,6-diamethyl-, 2,6-dichloro, 2,6-dibromo-, and 2,6-diiodo-derivatives 2-9, also nitrobenzene (1a), its 3-methyl-, 3-chloro-, 3-bromo-, and 3-iodo-derivatives 2a-5a and 3,5-dichloro- and 3,5-dibromo-derivatives 7a and 8a.Analysis of the chemical shifts of carbon bearing nitro group and nitro oxygens in these compounds suggests that presence of one substituent ortho- to the methoxyl group enhances its resonance interaction with the benzene ring whereas presence of two ortho-substituents inhibits this resonance.However, in no case the resonance is completely inhibited.The extent of enhancement or inhibition is almost independent of the nature of the ortho-substituent.This conclusion has also been arrived by analyzing the reported chemical shifts of the para-carbons in anisoles 1b-9b and the corresponding carbons in benzene derivatives 1c-9c.Though evidence could not be obtained for steric enhancement of resonance using methoxyl oxygen chemical shifts, analysis of these chemical shifts in di-ortho-substituted anisoles 6-9 and 6a furnishes evidence for steric inhibition of resonance.However, 15N chemical shifts are of no use in studying these phenomena.Semiempirical molecular orbital calculations using AM1 Hamiltonian suggest that the methoxyl group is coplanar with the benzene ring in anisole, 4-nitroanisole and 2-substituted-4-nitroanisoles but is perpendicular to the benzene ring in 2,6-disubstituted-4-nitroanisoles.Moreover, in 2-substituted-4-nitroanisoles the O-methyl group is anti to the 2-substituent.
- Pandiarajan, Karuppiah,Kabilan, Senthamaraikannan,Sankar, Punnaivanam,Kolehmainen,Erkki,Nevalainen, Tapio,Kauppinen, Reijo
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p. 2639 - 2646
(2007/10/02)
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- I. Photochemical nitration of methoxybenzenes from charge-transfer complexes with tetranitromethane
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The direct irradiation of the charge-transfer (CT) absorption band of the 1/1 electron donor-acceptor complexes of dimethoxybenzenes with tetranitromethane leads to aromatic nitration with a high quantum yield.The analogous methoxytoluenes under the same photochemical conditions are converted in equally high yields to products of aromatic trinitromethylation.This dichotomy with different methoxybenzenes (ArH) is discussed within the context of the common reactive intermediates derived from the CT excitation of the complex.The subsequent interactions of the geminate fragments, i.e., +., C(NO2)3-, .NO2>, by radical-pair and ion-pair annihilation represent a unifying mechanism for the CT photochemistry leading to aromatic nitration and trinitromethylation.
- Sankararaman, S.,Kochi, J. K.
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p. 278 - 285
(2007/10/02)
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