Refernces
10.1002/chem.201002076
The study presents the development of a series of eight new [2]rotaxane molecules, with a focus on the first sulfonamide interlocked system, designed to selectively recognize chloride anions in aqueous media. The research leverages a chloride-anion-templating synthetic pathway to create these [2]rotaxanes, whose three-dimensional interlocked-binding domains exhibit high chloride selectivity. The study utilizes 1H NMR spectroscopic titration to demonstrate the rotaxanes' chloride recognition capabilities and employs X-ray structural analysis and computational molecular dynamics simulations to elucidate the formation yields, anion binding affinities, and selectivity trends. The findings reveal that the rotaxanes can selectively bind chloride even in competitive aqueous solvent mixtures, with the binding affinity tunable through modifications such as electron-withdrawing substituents and charge increase. The research contributes to the advancement of anion recognition in supramolecular chemistry and has implications for nanotechnological applications.
10.1016/j.tet.2008.07.007
The study focuses on the synthesis of 1,4- and 1,5-disubstituted-1,2,3-triazolo-nucleosides from various alkynes using 10-azido-2,3,5-tri-O-acetylribose. The researchers employed copper-catalyzed azide-alkyne cycloaddition (CuAAC) and ruthenium-catalyzed azide-alkyne cycloaddition (RuAAC) methods. They optimized the RuAAC conditions using a commercially available catalyst, [Cp*RuCl(PPh3)2], under microwave heating, which significantly reduced the reaction time from 6 hours to 5 minutes and allowed the reaction to occur under water-containing conditions. Both CuAAC and RuAAC proved to be valuable tools for the synthesis of 1,2,3-triazolyl-nucleosides, which are potential therapeutic agents against DNA viruses and retroviruses, including hepatitis C virus (HCV). The synthesized compounds were evaluated for their anti-HCV activity in vitro, but none exhibited marked activity or toxicity. The study concludes that the developed methods provide an efficient approach to synthesize a small library of 1,5-disubstituted-triazolo derivatives under RuAAC and 1,4-regioisomers under CuAAC.
10.1021/om034385g
The study investigates the reactions of 3-(pentafluorophenyl)indene and (pentafluorophenyl)cyclopentadiene with tetrakis(dimethylamido)titanium(IV), resulting in the formation of products where one or both ortho fluorines of the C6F5 group are replaced by dimethylamino groups. This suggests a titanium-mediated, intramolecular nucleophilic aromatic substitution mechanism. The research led to the isolation of organic products and the conversion of substituted cyclopentadiene to a ferrocene derivative. The study provides insights into the selective activation of polyfluorinated organic compounds, a significant challenge in synthetic chemistry, and contributes to the understanding of transition metal complex mechanisms for C-F activation.
10.1002/adsc.200700333
The research focuses on the copper-catalyzed multicomponent reactions (MCRs) of terminal alkynes, acid chlorides, and carbodiimides to synthesize functionalized propiolamidine derivatives. The study explores the efficiency of various bases and solvents to optimize the reaction conditions. The optimal catalytic system was found to be a combination of CuI, triethylamine (TEA), and acetonitrile (CH3CN), yielding the desired products in good to excellent yields. The experiments involved a suspension of carbodiimide and acid chloride, followed by the addition of anhydrous acetonitrile, TEA, CuI, and alkyne at room temperature under a nitrogen atmosphere. The reaction mixture was stirred, then extracted with CH2Cl2, washed with saturated NaHCO3 solution and water, dried over anhydrous MgSO4, and evaporated under vacuum. The residue was purified using silica gel column chromatography with petroleum ether/ethyl acetate as the eluent. The analysis of the reaction products was based on isolated yields, which were calculated based on the amount of N,N’-dialkylcarbodiimides used.
10.1021/jo00214a007
The research investigates the oxidation of indans and tetralins to 1-indanones and 1-tetralones using Jones chromic acid and other Cr(VI) reagents. The study explores the effectiveness of the Jones reagent in oxidizing hydrocarbons at benzylic positions, comparing it with other Cr(VI) reagents like 2,2'-bipyridinium chlorochromate (BiPCC) and CrO3 in acetic acid. It was found that while the Jones reagent provides high yields of sterically hindered monoketones, it is less selective compared to other reagents. The research also examines the impact of various parameters on the oxidation process, including the use of different acids and solvents, the effect of excess sulfuric acid, and the role of drying agents like anhydrous magnesium sulfate and oven-dried silica gel in improving yield and reaction efficiency. Additionally, the stability of 1-tetralone under Jones oxidation conditions and the consumption of Cr(VI) and formation of acetic acid during the process were studied.
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