Volume 52, Nº 10 (2016)

An improved procedure was developed for the synthesis of 3,3,3-trifluoro-1-nitropropene, and a new representative of gem-bromonitroalkenes, 1-bromo-3,3,3-trifluoro-1-nitropropene, was synthesized therefrom. Its reaction with phenyl azide gave a mixture of two regioisomeric 1,2,3-triazoles, from which pure 5-nitro-1-phenyl-4-(trifluoromethyl)-1H-1,2,3-triazole was isolated.

A preparative procedure has been proposed for the alkylation of CH acids with halo acetals and hydrolysis of the alkylation products to furan derivatives and lactones.

Reactions of substituted benzenes C₆H₅R (R = Me, F, Cl, Br, CF₃, NO₂) with xenon difluoride in the presence of boron trifluoride–diethyl ether complex in weakly acidic (1,1,1,3,3-pentafluorobutane) and weakly basic media (acetonitrile) have been studied. These reactions lead to the formation of fluorobenzene derivatives FC₆H₄R (isomer mixture) together with isomeric difluorobenzenes and fluorinated and non-fluorinated biphenyls. The results have been compared with previously reported data obtained in other solvents using other catalysts.

As shown by the dipole moment method and quantum chemical calculations, (arylcarbamoylmethyl) diphenylphosphine oxides and sulfides exist as equilibrium mixtures of several rotational isomers stabilized by H · · · X intramolecular hydrogen bonds (X = O, S). The most energetically favorable rotamer and its fraction have been determined for each compound.

Decarboxylation of (heptafluoronaphthalen-2-yl)acetic acid in DMF in the presence of NaHCO₃ gave 2-methylheptafluoronaphthalene, and treatment with PCl₅ on heating afforded dichloro(heptafluoronaphthalen-2-yl)acetic acid. Decarboxylation of the latter in DMF led to the formation of 2-(dichloromethyl)-heptafluoronaphthalene which was converted to 2-(difluoromethyl)heptafluoronaphthalene by heating with cesium fluoride.

The condensation of 4,5-dimethoxy-2-(morpholin-4-yl)aniline with anthracene-9-carbaldehyde gave N-(anthracen-9-ylmethyl)-4,5-dimethoxy-2-(morpholin-4-yl)aniline, a selective and efficient fluorescent chemosensor for mercury(II) cations.

ω-(4-Oxo-1,4-dihydropyridin-2-yl)alkanamides were obtained from cycloalkanone oximes spirofused to 4-oxo-6-methyl-1,2,3,4-tetrahydropyridine fragment through the α-carbon atom and C², respectively, on heating in polyphosphoric acid. The resulting amides were converted to the corresponding acids and methyl esters. Methylation of 5-(6-methyl-4-oxo-1,4-dihydropyridin-2-yl)pentanamide with diazomethane gave 4-methoxypyridine derivative as the major product and a small amount of N-methyl derivative, 5-(1,6-di-methyl- 4-oxo-1,4-dihydropyridin-2-yl)pentanamide.

A procedure has been developed for the synthesis of highly functionalized 1,8-naphthyridines by three-component condensation of aromatic aldehydes with malononitrile dimer and enamino ketones.

2-Amino-4-(2,2-dichlorovinyl)-1,3-thiazole reacted with highly electrophilic N-(2,2-dichloro-2-phenylethylidene)- and N-(2,2,2-trichloroethylidene)arenesulfonamides through the exocyclic amino group to give products of nucleophilic addition to the azomethine bond, N-[2,2-di(or 2,2,2-tri)chloro-1-(1,3-thiazol-2-ylamino)ethyl]arenesulfonamides in good yields. Intramolecular heterocyclization of the latter afforded N-[3-(2,2-dichloroethyl)-6-phenylimidazo[2,1-b][1,3]thiazol-5-yl]arenesulfonamides.

3,5-Disubstituted 1,2,4-triazoles containing linear and cyclic amine fragments have been synthesized by thermal cyclization of N′-(1-iminoalkyl) hydrazides prepared by condensation of imido esters with carboxylic acid hydrazides. The initial imido esters have been synthesized by the Pinner reaction, as well as by reaction of nitriles with methanol in the presence of a catalytic amount of sodium methoxide. A procedure has been developed for the synthesis of 5-substituted 3-(3-nitrophenyl)-1,2,4-triazoles which have been converted to 3-aminophenyl derivatives by reduction with hydrazine hydrate over Raney nickel.

The formation of a porphyrin–fullerene dyad from 2′-(pyridin-4-yl)-5′-(pyridin-2-yl)-1′-(pyridin-3-ylmethyl)-2′,5′-dihydro-1′H-pyrrolo[3′,4′: 1,9](C₆₀-I_h)[5,6]fullerene and (2,3,7,8,12,13,17,18-octaethylporphyrinato) manganese(III) with axial chloride ligand has been studied on a quantitative level with the goal of obtaining supramolecules possessing biological activity. Preliminarily, the reaction of manganese(III) porphyrin with pyridine has been studied. The donor–acceptor dyads are formed either instantaneously and reversibly (pyridine) or slowly and irreversibly (substituted fullerene). In both cases, the reaction is a one-step process for which thermodynamic and kinetic parameters have been determined. The results can be used to optimize conditions for the synthesis of porphyrin–fullerene dyads. The obtained dyads have been characterized by spectral data and stability constants.