- Nucleophilic aromatic substitution for heteroatoms: An oxidative electrochemical approach
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The nucleophilic aromatic substitution for heteroatom through electrochemical oxidation of the intermediate σ-complexes (Meisenheimer complexes) in simple nitroaromatic compounds is reported for the first time (NASX process). The studies have been carried out with hydride, cyanide, fluoride, methoxy, and ethanethiolate anions and n-butylamine as a nucleophile, at the cyclic voltammetry (CV) and preparative electrolysis level. The cyclic voltammetry experiments allow for detection and characterization of the σ-complexes and they have led us to a proposal for the mechanism of the oxidation step. Furthermore, the power of the CV technique in the analysis of the reaction mixture throughout the whole chemical and electrochemical process is described.
- Gallardo, Iluminada,Guirado, Gonzalo,Marquet, Jordi
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- Arene Cyanation via Cation-Radical Accelerated-Nucleophilic Aromatic Substitution
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Herein we describe a cation radical-accelerated-nucleophilic aromatic substitution (CRA-SNAr) of alkoxy arenes utilizing a highly oxidizing acridinium photoredox catalyst and acetone cyanohydrin, an inexpensive and commercially available cyanide source. This cyanation is selective for carbon-oxygen (C-O) bond functionalization and is applicable to a range of methoxyarenes and dimethoxyarenes. Furthermore, computational studies provide a model for predicting regioselectivity and chemoselectivity in competitive C-H and C-O cyanation of methoxyarene cation radicals.
- Holmberg-Douglas, Natalie,Nicewicz, David A.
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supporting information
p. 7114 - 7118
(2019/09/07)
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- Design, synthesis, and biological evaluation of 5-(4-(pyridin-4-yl)-1H-1,2,3-triazol-1-yl)benzonitrile derivatives as xanthine oxidase inhibitors
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A series of 5-(4-(pyridin-4-yl)-1H-1,2,3-triazol-1-yl)benzonitrile derivatives (1a–p) was designed, synthesized, and identified as xanthine oxidase inhibitors with micromolar level potencies. Among them, the most promising compounds 1j and 1k were obtained with IC50 values of 8.1 and 6.7?μm, respectively. The Lineweaver–Burk plot revealed that compound 1k acted as a mixed-type xanthine oxidase inhibitor. SAR analysis revealed that a carbon atom occupying the X3 position is not as effective as a nitrogen atom, and an iso-pentyloxy or a cyclopentyloxy at the 2-position of benzonitrile moiety will benefit the inhibitory potency. The basis of xanthine oxidase inhibition by 1k was rationalized by molecular modeling studies.
- Zhang, Ting-Jian,Li, Song-Ye,Zhang, Yi,Wu, Qing-Xia,Meng, Fan-Hao
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p. 526 - 533
(2017/10/23)
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- BICYCLIC HETEROARYL SUBSTITUTED COMPOUNDS
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Disclosed are compounds of Formula (I) to (VIII): (I) (II) (III) (IV) (V) (VI) (VII) (VIII); or a stereoisomer, tautomer, pharmaceutically acceptable salt, solvate or prodrug thereof, wherein R3 is a bicyclic heteroaryl group substituted with zero to 3 R3a; and R1, R2, R3a, R4, and n are defined herein. Also disclosed are methods of using such compounds as PAR4 inhibitors, and pharmaceutical compositions comprising such compounds. These compounds are useful in inhibiting or preventing platelet aggregation, and are useful for the treatment of a thromboembolic disorder or the primary prophylaxis of a thromboembolic disorder.
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Page/Page column 720; 721
(2018/03/25)
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- A class of 4, 5 - disubstituted imidazole derivatives and its preparation and use (by machine translation)
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The invention relates to a compound of general formula I indicated by the 4, 5 - disubstituted imidazole compound, or its pharmaceutically acceptable salt, pharmaceutical composition containing the same and its preparation and use, the compounds can be used as a xanthine oxidase (Xanthine oxidase, XO) inhibitor, used for the treatment of uric acid crystallization at the joints to the deposition of Gout and its complications. (by machine translation)
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Paragraph 0109-0111
(2017/07/22)
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- 1-substituted phenyl-1H-1,2,3-triazole compound as well as preparation method and application thereof
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The invention relates to a 1-substituted phenyl-1H-1,2,3-triazole compound, in particular to a compound applicable to preparation of anti-gout drugs and a preparation method of the compound, and belongs to the field of medicines. The compound is as shown in the general formula, wherein each R1 is independent alkyl of 1-10 carbons, 3-10 carbon atom naphthenic bases, allyl, methoxy ethyl, benzyl and substituted benzyl; substituted benzyl can be p-halogenated benzyl, p-cyano benzyl and p-alkoxy benzyl; each R2 is independent H or methyl; each R3 is independent H or ethyl. Experimental results show that the compound has a good effect in the in-vitro xanthine oxidase inhibition activity test.
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- The element effect and nucleophilicity in nucleophilic aromatic photosubstitution (SNAR*). Local atom effects as mechanistic probes of very fast reactions
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(Chemical Equation Presented) Photoreactions of 4-nitroanisole and the 2-halo-4-nitroanisoles (halogen = F, Cl, Br, and I) with the nucleophiles hydroxide ion and pyridine have been investigated quantitatively to extend the findings recently communicated for cyanide ion. The halonitroanisoles on excitation form triplet π,π* states, which undergo substitution of the halogen by nucleophiles. Chemical yields of photoproducts, Stern-Volmer kinetic plots, triplet lifetimes, and triplet yields are reported for the five compounds with the three nucleophiles. Following a standard kinetic treatment, 73 rate constants are determined for elementary reactions of the triplets including quenching and various nucleophilic addition processes. The photoadditions are roughly 14 orders of magnitude faster than thermal counterparts. Rate constants for attack at the fluorine-bearing carbon of triplet 2-fluoro-4-nitroanisole are 2.9 × 109, 1.3 × 109, and 6.3 × 108 M-1 s-1 for cyanide ion, hydroxide ion, and pyridine, respectively. The relative rates for attack at the halogen-bearing carbons for F/Cl/Br/I are 27:1.9:1.9:1 (cyanide ion), 29:2.6:2.4:1 (hydroxide ion), and 39:3.9: 3.5:1 (pyridine), respectively. The relative nucleophilicities vary somewhat with the attack site; they are about 5:2:1 for cyanide ion, hydroxide ion, and pyridine for attack at the halogen-bearing carbons. The trend of the element effect opposes that of aliphatic substitution and elimination but is similar in size and parallel to that of thermal nucleophilic aromatic substitution. Relative nucleophilicities in the photoreactions are also similar to those of comparable but vastly slower thermal reactions. The findings imply that the efficiency-determining step of the halogen photosubstitution is simple formation of a σ-complex through electron-paired bonding within the triplet manifold.
- Wubbels, Gene G.,Brown, Toby R.,Babcock, Travis A.,Johnson, Kandra M.
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p. 1925 - 1934
(2008/09/19)
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- The element effect in nucleophilic aromatic photosubstitution (S N2Ar*)
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Photoreactions of 4-nitroanisole and the 2-halo-4-nitroanisoles (halogen == F, Cl, Br, I) with NaCN have been investigated. 4-Nitroanisole gave a novel, stable nitronate ion adduct (74%) with cyanide. For the five compounds, we report product distributions, Stern-Volmer kinetic plots, triplet lifetimes, and triplet yields, which afford rate constants for attack by the cyanide ion. Cyanide attack on the fluoride is diffusion controlled; the relative rates for attack at F, Cl, Br, and I are 27:2:2:1, respectively.
- Wubbels, Gene G.,Johnson, Kandra M.,Babcock, Travis A.
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p. 2803 - 2806
(2008/02/05)
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- Calcilytic compounds
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Novel arylalkylamino compounds exhibiting calcilytic properties are provided.
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- Effects of superoxide anion generated from aromatic radical anions produced in nucleophilic aromatic photosubstitution reactions
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Superoxide anion is generated from aromatic radical anions produced in nucleophilic aromatic photosubstitutions when the reactions are carried out in non-deoxygenated solutions of polar aprotic solvents. Superoxide anion thus generated displaces cyanide anion from acetonitrile and benzyl cyanide, ethoxide anion from ethyl acetate, and methanesulfenate anion from dimethyl sulfoxide. Hence, non-deoxygenated polar aprotic solvents should be avoided in nucleophilic aromatic photosubstitution reactions.
- Cervera, Maria,Marquet, Jordi
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p. 966 - 969
(2007/10/03)
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- Macrocyclic tetraazacyclododecane conjugates and their use as diagnostic and therapeutic agents
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A group conjugates having a functionalized polyaminocarboxylate chelant that form complexes with rare earth-type metal ions, covalently attached to an antibody or antibody fragment, can be used for therapeutic and/or diagnostic purposes.
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- PHOTOCYANATION OF 3,4-DIMETHOXY-1-NITROBENZENE. A QUANTITATIVE STUDY
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UV photolysis (365 nm) of 3,4-dimethoxy-1-nitrobenzene in the presence of potassium cyanide leading to 3-cyano-4-methoxy-1-nitrobenzene was subjected to a quantitative photokinetic study.The reaction exhibits a second order kinetics with respect to the nucleophile and is effectively quenched by molecular oxygen as well as 2,4-hexadienoic acid.The excited triplet lifetime of 0.9 microseconds was determined on the basis of the dependence of quantum yield on the nucleophile and quencher concentrations in 50percent aqueous tert-butanol.The quantum yield of intersystem crossing is at least 0.38 in the same solvent; bimolecular rate constant for the interaction of triplet 3,4-dimethoxy-1-nitrobenzene with cyanide anion has the value of 5.6*108 l*mol-1*s-1, which is approximately one half of the rate constant for diffusion controlled quenching.Quantum yield of the reaction is strongly dependent on the water content in mixtures with tert-butanol and increases from 0.04 in water to 0.68 in 88percent tert-butanol.
- Kuzmic, Petr,Soucek, Milan
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p. 358 - 367
(2007/10/02)
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- Cyano and Nitro Group Effect on the Rate of Methoxy Denitration Reaction in the Pyrrole and Benzene Ring
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In both the pyrrole and benzene ring the methoxy denitration reaction is accelerated by a nitro or a cyano group flanking the reaction center.However, because of the different geometry of the rings, in the pyrrole ring a nitro group is more effective than a cyano group, at variance whit what is observed in the benzene ring.
- Bazzano, Francesca,Mencarelli, Paolo,Stegel, Franco
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p. 2375 - 2377
(2007/10/02)
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