Refernces
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.
10.1016/j.tetlet.2004.09.025
The study presents a novel approach for constructing quaternary centers on cycloalkane rings, which is a significant challenge in synthetic chemistry. The researchers utilized a combination of Birch reduction-allylation and Cope rearrangement on o-anisic acid derivatives to synthesize 2-acyl-3-cyclohexenone derivatives. They successfully generated rearrangement substrates and achieved high yields of 2-cyclohexenone products through thermal equilibration in 1,2-dichlorobenzene. Notably, the Cope rearrangement of a specific substrate resulted in the formation of a new quaternary center with excellent yield, marking the first example of such synthesis on a cycloalkenone ring via Cope rearrangement. This method could serve as a powerful tool for creating substituted 2-cyclohexenones, offering a potentially versatile synthetic intermediate with potential for 1,3-chirality transfer and access to enantiomerically pure products.
10.1055/s-0031-1291135
The study focuses on the copper-catalyzed 1,3-dipolar cycloaddition of (arylselanyl)alkynes with benzyl azides, producing a series of novel [(arylselanyl)alkyl]-1,2,3-triazoles. This reaction, known as click chemistry, was performed under mild conditions using copper(II) acetate monohydrate and sodium ascorbate as catalysts. Various substituted benzyl azides, both electron-withdrawing and electron-donating, were reacted with different (arylselanyl)alkynes, yielding high amounts of selenium-containing triazoles. The synthesized compounds show potential for biological applications, expanding the utility of selenium-containing heterocycles in organic chemistry.
10.1007/s11164-015-1961-1
The research focuses on the efficient one-pot synthesis of 2-oxazoline derivatives, which are significant in pharmaceutical and material science due to their presence in biologically active compounds and use as intermediates in organic synthesis. The study presents a method utilizing molecular iodine as a catalyst and potassium carbonate in tert-Butyl alcohol (t-BuOH) under ultrasound irradiation at 35–40°C for the condensation of aldehydes with 2-aminoethanol. The reaction's efficiency is optimized by varying the amounts of molecular iodine and 2-aminoethanol, the reaction temperature, and the solvent. The experiments involve monitoring the reaction through thin-layer chromatography (TLC) and characterizing the products using melting points, optical rotations, and spectroscopic techniques such as 1H NMR, 13C NMR, and mass spectrometry. The results show that the method yields moderate to good results with a simple work-up procedure, offering a mild and practical approach to 2-oxazoline synthesis.
10.1080/00397911.2019.1681001
The research focuses on the catalyst-free cyclocondensation of β-ethylthio-β-indolyl-α, β-unsaturated ketones with hydrazines, leading to the efficient synthesis of 3-pyrazolyl indoles. This method avoids the use of large excesses of catalysts such as acids and bases, thus reducing the discharge of harmful chemicals and addressing environmental and safety concerns. The reactants used in the study include β-ethylthio-β-indolyl-α, β-unsaturated ketones and hydrazine hydrate. The experiments were optimized to achieve excellent yields under the best conditions, which were found to be a 1:2 molar ratio of ketones to hydrazine, using tert-butyl alcohol as the solvent, and conducting the reaction at 120°C for 4 hours in a sealed tube. The synthesized compounds were characterized using spectral and analytical data, including 1H and 13C NMR spectra recorded on a Bruker DRX-600 spectrometer, HRMS analysis on a Bruck micro Tof using ESI method, and melting points were determined without correction. The reaction products were purified by silica gel column chromatography, and their structures were confirmed with the help of these analyses.
10.1021/j100350a029
The study investigates the sonochemistry of argon-saturated water-alcohol mixtures using ESR and spin trapping with 3,5-dibromo-4-nitrosobenzenesulfonate (DBNBS). It examines free-radical intermediates induced by 50-kHz ultrasound in aqueous solutions of ethanol, 1-propanol, 2-propanol, and 2-methyl-2-propanol. The chemicals involved include various alcohols (ethanol, 1-propanol, 2-propanol, 2-methyl-2-propanol, methanol), water (H2O), deuterated water (D2O), and DBNBS as the spin trap. The alcohols serve as the primary solutes under investigation, while water and deuterated water act as solvents and provide isotopic labeling for tracking reactions. DBNBS is crucial for capturing and identifying radicals formed during sonolysis through its spin adducts. The study identifies spin adducts typical of thermal decomposition of the alcohols and of H- and OH-induced abstraction reactions, observes isotopically mixed radicals in mixed-isotope systems, and examines the effects of solvent composition and temperature on the sonochemical yields of radicals.
10.1016/S0008-6215(00)80546-7
The research details an investigation into the reaction of diglycolaldehyde with various alcohols in acid media, focusing on how the degree of α-substitution of the alcohol affects the nature of the products formed. The study aimed to understand the influence of alcohol substitution on the formation of acetals and cyclic compounds. The researchers found that the proportion of cyclic acetals increased with higher α-substitution in the alcohols. They used methanol, ethanol, 1-propanol, 2-propanol, and 2-methyl-2-propanol, among others, to react with diglycolaldehyde under both room temperature and reflux conditions. The products were separated by distillation, and the mixtures of cyclic isomers were resolved by column chromatography. The study concluded that diglycolaldehyde bis(dimethyl acetal) was the only acetal isolated when methanol was used, while mixtures of acyclic acetals and stereoisomers of 2,6-dialkoxy-1,4-dioxanes were obtained with other alcohols. The reactions were assumed to have reached equilibrium, and the results suggested that the nature of the products was significantly influenced by the alcohol's α-substitution degree.
10.1055/s-2003-44986
The study presents a convenient protocol for the esterification of carboxylic acids with alcohols using di-t-butyl dicarbonate [(BOC)2O] as an activating agent and catalytic amounts of N,N-dimethylaminopyridine (DMAP). The reaction involves mixing stoichiometric amounts of carboxylic acids and primary or secondary alcohols, which are then treated with (BOC)2O in the presence of DMAP to produce the corresponding esters. The byproducts, t-butanol and CO2, are volatile, simplifying the purification process compared to the standard DCC/DMAP method. The study optimizes reaction conditions, such as temperature and solvent choice, and demonstrates the protocol's broad applicability with various alcohols and carboxylic acids, including those with sensitive functional groups. The method is particularly useful for preparative chemistry, combinatorial chemistry, and drug discovery due to its tolerance of a wide range of functionalities and the ease of product purification.
Xn, 
F, 
T
F:Flammable;
