Alkylation of 6-Polyfluoroalkyl-2-thiouracils with Haloalkanes

Russian Journal of Organic Chemistry - The structure of 6-polyfluoroalkyl-2-thiouracils and reactivity of nucleophilic centers in their molecules were analyzed by quantum chemical calculations....     

A comparative study of the reactions of fluorinated oxi- and thiiranes with acyl chlorides

The CoCl₂-catalyzed reactions of fluorinated 1,2-oxi- and thiiranes with acyl chlorides were studied. It was found that a regioselective heterocycle opening reaction resulted in two isomers having normal and abnormal structure in a ratio predetermined by the substituents in both the starting heterocycles and acyl chlorides.     

Alkylation of 2-(methylsulfanyl)-6-polyfluoroalkylpyrimidin-4(3<Emphasis Type="Italic">H</Emphasis>)-ones with haloalkanes

The alkylation of ambident anions of 2-(methylsulfanyl)-6-(polyfluoroalkyl)pyrimidin-4(3H)-ones with 4-bromobutyl acetate leads to concurrent formation of O- and N-(4-acetoxybutyl) derivatives. Polar aprotic solvents favor formation of the O-isomer, and weakly polar dioxane favors N-alkylation. The reaction of 2-(methylsulfanyl)-6-(trifluoromethyl)pyrimidin-4(3H)-one with an equimolar amount of 1,2-dibromoethane in polar acetonitrile gives a mixture of N,N-, O,O-, and N,O-bridged bis-pyrimidines, as well as N- and O-[2-(methylsulfanyl)ethyl] derivatives, whereas in the presence of 10 equiv of 1,2-dibromoethane the N,O-isomer is formed as the only product. The reaction in weakly polar tetrahydrofuran yields N,N- and N,O-bispyrimidines.     

A Convenient Approach to 4,7‐Dihydrotetrazolo [5,1‐c][1,2,4]triazine Synthesis

Azo coupling of 1,3‐dicarbonyl compounds with tetrazolyl‐5‐diazonium chloride is used to develop a convenient one‐step procedure for the synthesis of 4,7‐dihydrotetrazolo[5,1‐c][1,2,4]triazines. In contrast to nonfluorinated analogs, 7‐hydroxy‐7‐polyfluoroalkyl‐4,7‐dihydrotetrazolo[5,1‐c][1,2,4]triazines undergo a ring‐chain isomerism resulting from the cleavage at the C7―N7a bond. A distinctive feature of nonfluorinated 4,7‐dihydrotetrazolo[5,1‐c][1,2,4]triazines is the possibility to dehydration, which is accompanied by an azide rearrangement due to the tetrazole ring cleavage with the formation of tetrazolo[1,5‐b][1,2,4]triazines.     

Inhibitory activity of fluorine-containing quaternary ammonium salts comprising an N-methylpiperazinyl moiety

New fluorine-containing quaternary ammonium salts comprising an N-methylpiperazinyl moiety, which exhibited a high inhibiting capacity against hydrochloric acid corrosion of low-carbon steel, were synthesized. The polarization-resistance method was applied to determine the uniform corrosion rate of steel-3 in relation to the structure and concentration of the fluorine-containing substituents in the salts. It was found that the structure of the fluorine-containing moiety of the quaternary ammonium salts does not significantly influence the corrosion processes.     

Modification of the silica particles surface with perfluoroalkylmethyloxiranes

Silica particles have been prepared via the sol-gel process in the presence of perfluoropropyl- and perfluorobutylmethyloxiranes. Nanoparticles are formed in the presence of acidic catalyst. Under conditions of basic catalysis the attack of silanol group (formed in situ via hydrolysis of tetraethoxysilane) on the oxirane ring leads likely to the Si-O-C bond formation.     

Perfluoro(1,2-epoxycyclohexane) in the synthesis of fluorinated heterocycles

Perfluoro(1,2-epoxycyclohexane) readily reacts with bifunctional nucleophiles (urea, thiourea, and benzene-1,2-diamine) via opening of the oxirane ring and subsequent heterocyclization to give fluorinated benzimidazole, 1,3-benzothiazole, and phenazine derivatives, respectively.     

Synthesis of New Heteroatomic Podands from Ethyl 2-[(2-Aminophenylamino)Methylidene]-3-Oxoalkanoates and Thiophene-2,5-Dicarboxaldehyde

Condensation of two moles of ethyl 2-[(2-aminophenylamino)methylidene]-3-oxo-3-(polyfluoroalkyl)propionates with 2,5-thiophene-dicarboxaldehyde results in new heteroatomic podands. X-ray data showed that in the solid state these molecules arrange in two independent chelating fragments of b-amino enone type, thiophene fragment being a spacer.     

A concise approach to CF3-containing furan-3-ones, (bis)pyrazoles from novel fluorinated building blocks based on 2,3-butanedione

1,1,1-Trifluoro-4,5,5-trimethoxyhex-3-en-2-one and lithium (2Z)-1,1,1-trifluoro-5,5-dialkoxy-4-oxohex-2-en-2-olate were synthesized for the first time via direct trifluoroacetylation of 2,3-butanedione acetal derivatives. A simple and effective approach to acetal or acyl substituted CF₃-pyrazoles, 5,5′-bis(trifluoromethyl)-3,3′-bipyrazole, and, to 5-trifluoromethylfuran-3-ones is presented.     

Bis(1,1,1,3,5,5,5-heptafluoro-4-iminopent-2-ene-2-aminato)copper(<Emphasis Type="SmallCaps">ii</Emphasis>) — a new metal-containing matrix in the design of heterospin systems

The first heterospin compounds based on bis(1,1,1,3,5,5,5-heptafluoro-4-iminopent-2-ene-2-aminato)copper(ii) (CuL₂) and nitronyl nitroxide radicals, 2-R-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyls (NIT-R, where R = H, Me, Ph, and 1-methylpyrazol-4-yl), were synthesized and structurally characterized. An important peculiarity of the structure of synthesized solid phases is the formation of a supramolecular structure due to hydrogen bonds between the oxygen atoms of the nitronyl nitroxide fragments of NIT-R and the hydrogen atoms of the NH groups of CuL₂.