Russian Journal of Organic Chemistry最新文献

We report an environmentally friendly synthesis of titanium dioxide nanoparticles (TiO₂ NPs) using titanium oxyhydroxide [TiO(OH)₂] and the fungus strain Aspergillus niger isolated from a pond ecosystem. The mycogenic TiO₂ NPs were characterized using FT-IR, XRD, FE-SEM, and TEM techniques. The Aspergillus niger-mediated TiO₂ NPs functioned as an efficient, eco-friendly, and recyclable catalyst for the one-pot, three-component synthesis of 2-amino-4H-1-benzopyrans in aqueous medium at room temperature. A library of structurally diverse 2-amino-4H-1-benzopyran derivatives was thus synthesized and screened for antimicrobial activity against two bacterial strains (Escherichia coli and Bacillus subtilis) and two fungal strains (Aspergillus niger and Saccharomyces cerevisiae). Several compounds exhibited good to excellent antimicrobial activity. The developed protocol offers several notable advantages, including simple catalyst preparation, green reaction conditions, catalyst reusability, high yields, short reaction times, and easy purification.

A novel and efficient method for synthesizing substituted β-trifluoromethyl styrenes through a copper-catalyzed desulfitative trifluoromethylation reaction was developed. This innovative approach utilizes 2-phenylethenesulfinic acid as a substrate and sodium trifluoromethanesulfinate as a CF₃ source under relatively mild reaction conditions. Notably, this protocol demonstrates remarkable stereoselectivity and wide substrate compatibility, offering a versatile platform for the preparation of β-trifluoromethyl styrene derivatives.

Chemodivergent synthesis of 2-(benzenesulfonyl)pyridine and pyridin-2-yl benzenesulfinate from 2-iodopyridine and sodium benzenesulfinate has been achieved using visible light nickel/photoredox catalysis (λ 450 nm, 30 W). The selectivity for C–S or C–O coupling has been found to depend on the photocatalyst nature.

Possible steric structures of transition states in thermal isomerization of five-membered aromatic heterocycles C₄H₃FX (X = NH, O, S) in an inert atmosphere have been simulated on the basis of analysis of isospectral molecular graphs. The formation of transition states is ensured by stabilization effect of the fragmented parts of the initial conjugated π-electron system. The geometric parameters and energies of the ground and transition states of C₄H₃FX (X = NH, O, S) have been calculated by the DFT/B3LYP/6-31G(d) method. Possible thermal isomerization pathways of 2-fluoro-1H-pyrrole, 2-fluorofuran, and 2-fluorothiophene molecules have been proposed, and mechanisms of [2,3]-rearrangement of substituents in these heterocycles have been established. Thermal [2,3]-rearrangements of 2-fluoro-1H-pyrrole, 2-fluorothiophene, and 2-fluoro­furan involve intermediate formation of nonaromatic isomers belonging to the Dewar benzene type.

A manganese(III)-catalyzed cross-dehydrogenative coupling of 2-aroylbenzofurans with phosphites to afford 2-aroyl-3-phosphonylbenzofurans is reported. The reaction proceeds via oxidation of dialkyl phos­phonates to phosphoryl radicals by manganese(III) cations, which are subsequently reduced to manganese(II). This is followed by electron transfer, electrophilic addition, and sequential intermediate transformations that lead to the formation of the desired 2-aroyl-3-phosphonylbenzofurans. A series of 2-aroyl-3-phosphonyl­benzofurans bearing various functional groups were synthesized in moderate to good yields. Molecular docking studies were performed to evaluate their inhibitory potential against the DNA gyrase enzyme. In addition, pharmacokinetic properties were assessed. Among the compounds tested, ligand 3c exhibited strong binding affinity (–7.8 kcal/mol) via hydrogen bonding, π–π stacking, and hydrophobic interactions.

Palladium-catalyzed arylation of tris(3-aminopropyl)amine (TRPN) with a number of aryl halides, including 1- and 2-bromonaphthalenes, 1- and 2-chloroanthracenes, 9-bromoanthracene, 9-bromophenanthrene, and 1-bromopyrene, afforded the corresponding N,N′,N″-triaryl derivatives. Almost quantitative yields of the target products were obtained in the reactions with 1-chloro- and 9-bromoanthracenes. Study of the fluorescence spectra of the synthesized compounds in the presence of different metal salts revealed complete or very strong fluorescence quenching of naphthalen-1-yl, anthracen-2-yl, and phenanthren-9-yl derivatives upon addition of Cu(II), Al(III), and Cr(III) perchlorates. Complete fluorescence quenching of pyren-1-yl derivative was observed on in the presence of copper ions. Some other metal cations induced small changes in the emission intensity with a blue shift of the fluorescence maximum by about 10 nm. Characteristic changes in the electronic absorption spectra of napththalen-1-yl, anthracen-9-yl, and pyren-1-yl derivatives in the presence of Cu(II), Al(III), and Cr(III) ions make these compounds promising for fluorescent and spectrophotometric detection of Cu(II), Al(III), and Cr(III) ions.

Conditions have been proposed for the addition of allyl bromide to the Diels–Alder adduct of levoglucosenone and piperylene. The reaction direction has been found to be largely determined by the solvent. The best result was obtained in tetrahydrofuran.

N-Arylation of a number of adamantane-containing amines with iodobenzene and its derivatives bearing electron-donating and electron-withdrawing substituents at the para or meta position was studied using unsupported copper and copper oxide nanoparticles as catalysts. The best yields of the target N-aryl derivatives were achieved in DMSO at 110°C in the presence of the catalytic system CuNPs 10/80 nm/rac-BINOL. In some cases, the use of 2-acetylcyclohexanone or 2-isobutyrylcyclohexanone as a ligand and DMF as a solvent at 140°C was possible. The maximum yields of N-arylamines exceeded 90%. The efficiency of the arylation reaction was found to depend on the substrate structure, whereas the effect of substituents in the aromatic ring was not so significant. Study of the copper leaching to solution in the course of the model reaction showed that the degree of leaching depends on the ligand nature. For comparison, N-heteroarylation of adamantane-containing amines with trifluoromethyl-substituted 2-bromopyridines was found to be accompanied by more significant leaching of copper. According to the transmission electron microscopy, electron diffraction, and energy-dispersive X-ray spectroscopy data, copper nanoparticles with an average particle size of 25 nm are converted during the reaction mainly to copper(I) oxide, the average particle size remaining almost unchanged.

Novel 1-[(1-phenyl-1H-1,2,3-triazol-5-yl)methyl]-4-(pyridin-2-yl)piperazine hybrids (7a–7h) were synthesized from 1-(2-pyridyl)piperazine and aromatic azides by click chemistry reaction in presence of Cu(II) and aqueous sodium ascorbate as catalyst. The ¹H and ¹³C NMR and mass spectral techniques were used to characterize the newly obtained hybrids. The analogues were also screened for in vitro anticancer activity, and the results were correlated with molecular docking studies. Compounds having nitro group on the phenyltriazole moiety were found to be the most active against the tested cancer cell. The docking studies of these hybrids revealed that compound 7a has greater affinity for the target receptor 4XO6 (MCF-7) and 5EQG (HepG2) proteins. These results emphasize the potential of 1-[(1-phenyl-1H-1,2,3-triazol-5-yl)methyl]-4-(pyridin-2-yl)­piperazine hybrids, making them strong contenders for further studies with the goal of developing more potent biological agents.

Multicomponent reaction of 4-nitrobenzaldehyde, cyanothioacetamide, N-(2-methylphenyl)-3-oxo­butanamide, and alkyl halides in boiling ethanol in the presence of 2 equiv of potassium hydroxide afforded 5-cyano-2-methyl-N-(2-methylphenyl)-4-(4-nitrophenyl)-6-sulfanylidene-1,6-dihydropyridine-3-carboxamide derivatives such as 2-(alkylsulfanyl)pyridines and 3-aminothieno[2,3-b]pyridines in 64–91% yields.