- Steric hindrance as a key factor on proton transfer in the σ-adduct forming reactions of o-substituted anilines with 1,3,5-trinitrobenzene in dimethylsulfoxide
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Kinetic and equilibrium studies are reported of the reactions of 1,3,5-trinitrobenzene (TNB) with a series of o-substituted anilines in dimethyl sulfoxide (DMSO) in the presence of 1,4-diazabicyclo[2.2.2.]octane (DABCO). The pKa values in DMSO for the aniline derivatives were measured using the proton-transfer equilibrium with 2,4-dinitrophenol. Kinetic studies are compatible with a two-step process involving initial nucleophilic attack on TNB by amine to give a zwitterionic intermediate which may transfer an acidic proton to DABCO to yield the anionic product. The results indicate steric hindrance to proton transfer in reactions involving 2,6-disubstituted anilines.
- Asghar, Basim H.
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Read Online
- Selective and Additive-Free Hydrogenation of Nitroarenes Mediated by a DMSO-Tagged Molecular Cobalt Corrole Catalyst
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We report on the first cobalt corrole that effectively mediates the homogeneous hydrogenation of structurally diverse nitroarenes to afford the corresponding amines. The given catalyst is easily assembled prior to use from 4-tert-butylbenzaldehyde and pyrrole followed by metalation of the resulting corrole macrocycle with cobalt(II) acetate. The thus-prepared complex is self-contained in that the hydrogenation protocol is free from the requirement for adding any auxiliary reagent to elicit the catalytic activity of the applied metal complex. Moreover, a containment system is not required for the assembly of the hydrogenation reaction set-up as both the autoclave and the reaction vessels are readily charged under a regular laboratory atmosphere.
- Sch?fberger, Wolfgang,Timelthaler, Daniel,Topf, Christoph
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supporting information
p. 2114 - 2120
(2021/07/22)
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- Synthesis of 7-halo indoles (by machine translation)
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The present invention relates to synthesis of 7? Halo indole method, comprising the steps of:O-halogenated aniline, chloral hydrate and hydroxylamine hydrochloride by the Sandmeyer reaction to synthesize 7? halogenating isatin ; 7? halogenating isatin dissolved with an organic solvent, in the reducing agent by reduction reaction under the conditions of 7? Halo indole, the reducing agent is an alkali metal borohydride system, four system adopts, lithium hydride system or triethyl silane system. The beneficial effect of the invention is:in order to O-halogenated aniline and the chloral hydrate is, hydroxylamine hydrochloride as raw materials, by the Sandmeyer shall synthesis method for preparing compositions b isonitroso 7? halogenating isatin, and then by further reduction and system reduction to prepare 7? Halo indole; by the 7? Preparation halogenating isatin 7? Halo indole method, the raw material is easy to obtain, low price, higher process yield, the product purity is good, simple operation, and the like, is suitable for batch preparation 7? Halo indole. (by machine translation)
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Paragraph 0021
(2017/01/12)
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- Mild N-deacylation of secondary amides by alkylation with organocerium reagents
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Secondary amides are a class of highly stable compounds serving as versatile starting materials, intermediates and directing groups (amido groups) in organic synthesis. The direct deacylation of secondary amides to release amines is an important transformation in organic synthesis. Here, we report a protocol for the deacylation of secondary amides and isolation of amines. The method is based on the activation of amides with Tf2O, followed by addition of organocerium reagents, and acidic work-up. The reaction proceeded under mild conditions and afforded the corresponding amines, isolated as their hydrochloride salts, in good yields. In combination with the C-H activation functionalization methodology, the method is applicable to the functionalization of aniline as well as conversion of carboxylic derivatives to functionalized ketones.
- Wang, Ai-E.,Chang, Zong,Liu, Yong-Peng,Huang, Pei-Qiang
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supporting information
p. 1055 - 1058
(2015/09/01)
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- The ortho effect on the acidic and alkaline hydrolysis of substituted formanilides
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The kinetics of formanilides hydrolysis were determined under first-order conditions in hydrochloric acid (0.01-8 M, 20-60°C) and in hydroxide solutions (0.01-3 M, 25 and 40°C). Under acidic conditions, second-order specific acid catalytic constants were used to construct Hammett plots. The ortho effect was analyzed using the Fujita-Nishioka method. In alkaline solutions, hydrolysis displayed both first- and second-order dependence in the hydroxide concentration. The specific base catalytic constants were used to construct Hammett plots. Ortho effects were evaluated for the first-order dependence on the hydroxide concentration. Formanilide hydrolyzes in acidic solutions by specific acid catalysis, and the kinetic study results were consistent with the AAC2 mechanism. Ortho substitution led to a decrease in the rates of reaction due to steric inhibition of resonance, retardation due to steric bulk, and through space interactions. The primary hydrolytic pathway in alkaline solutions was consistent with a modified BAC2 mechanism. The Hammett plots for hydrolysis of meta- and para-substituted formanilides in 0.10 M sodium hydroxide solutions did not show substituent effects; however, ortho substitution led to a decrease in rate constants proportional to the steric bulk of the substituent.
- Desai, Salil Dileep,Kirsch, Lee E.
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p. 471 - 488
(2015/06/30)
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- Synthesis, cytotoxic evaluation, and in silico studies of substituted N-alkylbromo-benzothiazoles
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In efforts to develop a new class of anticancer agents with improved efficacy and selective action, a series of N-alkylbromo-benzothiazoles were synthesized and evaluated for in vitro cytotoxic activity against various human cancer cell lines such as lung (A-549), prostate (PC-3), leukemia (THP-1), and colon (Caco-2). They were found to be highly active against prostate (PC-3) and leukemia (THP-1) cancer cells, moderately active against colon (Caco-2) cancer cells and less active against lung (A-549) cancer cells. Of the 12 compounds, two (11d, 11j) exhibit IC50 values of ≤ 1 μM against leukemia (THP-1) cancer cell lines. Compound 11l showed significant cytotoxic activity against the PC-3 (IC50 = 0.6 μM), THP-1 (IC50 = 3 μM) and Caco-2 cell lines (IC50 = 9.9 μM), respectively. Docking study of the synthesized ligand was done on epidermal growth factor receptor using ArgusLab flexible docking, to determine their observed activity. Further QSAR investigations with stepwise multiple linear regression analysis were applied to find correlation between various physicochemical parameters and anticancer activity. The QSAR results showed that anticancer activity could be modeled with descriptors. The predictive ability of models was cross-validated by observation of the low residual activity values and adjusted coefficient of variation (radj2) obtained by leave-one-out technique.
- Gill, Rupinder Kaur,Singh, Gagandeep,Sharma, Anuradha,Bedi,Saxena
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p. 4211 - 4222
(2013/09/02)
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- Weak halogen bonding in solid haloanilinium halides probed directly via chlorine-35, bromine-81, and iodine-127 NMR spectroscopy
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A series of monohaloanilinium halides exhibiting weak halogen bonding (XB) has been prepared and characterized by 35Cl, 81Br, and 127I solid-state nuclear magnetic resonance (SSNMR) spectroscopy in magnetic fields of up to 21.1 T. The quadrupolar and chemical shift (CS) tensor parameters for halide ions (Cl-, Br-, I-) which act as electron density donors in the halogen bonds of these compounds are measured to provide insight into the possible relationship between halogen bonding and NMR observables. The NMR data for certain series of related compounds are strongly indicative of when such compounds pack in the same space group, thus providing practical structural information. Careful interpretation of the NMR data in the context of novel and previously available X-ray crystallographic data, and new gauge-including projector-augmented-wave density functional theory (GIPAW DFT) calculations has revealed several notable trends. When a series of related compounds pack in the same space group, it has been possible to interpret trends in the NMR data in terms of the strength of the halogen bond. For example, in isostructural series, the halide quadrupolar coupling constant was found to increase as the halogen bond weakens. In the case of a series of haloanilinium bromides, the 81Br isotropic chemical shift and CS tensor span both decrease as the bromide-halogen XB is weakened. These trends were reproduced using both GIPAW DFT and cluster-model calculations of the bromide ion magnetic shielding tensor. Such trends are particularly exciting given the well-known role that NMR has played historically in the characterization of hydrogen bonding.
- Attrell, Robert J.,Widdifield, Cory M.,Korobkov, Ilia,Bryce, David L.
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experimental part
p. 1641 - 1653
(2012/06/30)
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- Anti-viral method
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PCT No. PCT/US97/07431 Sec. 371 Date Jan. 6, 1999 Sec. 102(e) Date Jan. 6, 1999 PCT Filed May 2, 1997 PCT Pub. No. WO97/41846 PCT Pub. Date Nov. 13, 1997The present invention provides compounds which inhibit an envelope virus by inhibiting the fusion of the virus with the host cell. The virus may be inhibited in an infected cell, a cell susceptible of infection or a mammal in need thereof.
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- 4-substituted quinoline derivatives having fungicidal activity
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This invention provides compounds of formula (1) STR1 wherein the substituents are described in the specification. The compounds of formula (1) are plant fungicides.
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- Urea, thiourea and guanidine compounds and their use as anti-viral agents
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The present invention provides compounds which inhibit an envelope virus by inhibiting the fusion of the virus with the host cell. The virus may be inhibited in an infected cell, a cell susceptible of infection or a mammal in need thereof.
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