D. L. Chizhov

2,4-Bridged 1,5-bis(fluoroalkyl)-1,3,5-triketones: synthesis and properties

Abstract Symmetrical and unsymmetrical bis-fluoroacylcyclopentanones and cyclohexanones were synthesized. NMR data reveal that the keto–enol tautomeric equilibrium is changed markedly by the presence of a trimethylene bridge compared to an ethylene moiety. A considerable influence of the fluoroalkyl chain length was found for 2,6-(bisfluoroacyl)cyclohexanones.

Synthesis, structure, electrochemical and magnetic properties of 2,6-bis(5-trifluoromethylpyrazol-3-yl)pyridine and its NiII complexes

Abstract2,6-Bis(5-trifluoromethylpyrazol-3-yl)pyridine (H2L) and its mono-, tri-, and tetranuclear NiII complexes were synthesized for the first time. All the obtained compounds were characterized by single-crystal X-ray diffraction analysis. In the complexes, 2,6-bis(5-trifluoromethylpyrazol-3-yl)pyridine exists in the neutral and dianionic forms and exhibits different coordination modes (κ3-, μ2-κ3:κ1-, and μ3-κ3:κ1:κ1). The electrochemical and magnetic properties of all compounds were studied. The tetranuclear NiII complex with the L2− dianion is reduced in two sequential reversible one-electron steps.

Synthesis of bis(polyfluoroalkyl)-1,3,5-triketones

A preparative procedure was developed for the synthesis of polyfluoroalkyl-1,3,5-triketones by condensation of acetone or fluorinated methyl β-diketones with methyl perfluorocarboxylates in the presence of LiH. In the case of CF3 substituents, the formation of triketone was accompanied by the formation of its cyclic hydrate, viz., of dihydroxytetrahydropyranone.

Unusual transformations of lithium enolate of ethyl 4,4,4-trifluoro-3-oxobutanoate

The present paper describes unusual reactions of lithium enolate of ethyl 4,4,4-trifluoro-3-oxobutanoate with ammonium acetate and 1-aminonaphthalene. These reactions produce 4-amino-2,6-bis(trifluoromethyl)pyridine and 4-trifluoromethyl-2-[(Z)-1,1,1-trifluoroprop-1-en-2-ol-1-yl]benzo[h]quinoline, respectively. The reaction of 1,1,7,7,7-hexafluoroheptane-2,4,6-trione hydrate with 1-naphthylamine gives a mixture of 4-trifluoromethyl-2-[(Z)-1,1,1-trifluoroprop-1-en-2-ol-1-yl]benzo[h]quinoline and N,N′-bis(naphth-1-yl)-2,6-bis(trifluoromethyl)pyridine-4(1H)-imine, respectively.

Isomerization as a tool to design volatile heterometallic complexes with methoxy-substituted β-diketonates

Abstract A series of new heterometallic compounds have been obtained by the co-crystallization of Cu(II) methoxy-substituted β-diketonates and Pb(II) hexafluoroacetylacetonate (hfac) from organic solvents. Their crystal structures were established by X-ray analysis. It is shown that the formation of heterometallic compounds proceeds with geometrical isomerization of the initial copper complexes, which can be controlled by varying terminal substituents in the ligand. Due to the ability of copper complexes to isomerize, the structure of the resulting heterocomplexes can be flexibly and purposefully changed from polymeric to discrete molecular forms. The study of the thermal properties shows that all the reported compounds are volatile and can be re-sublimed in a vacuum, with their composition and structure being retained.

Synthesis of perfluoroalkyl-containing tri- and tetradentate β-amino enones

Reactions of perfluoroalkyl-containing aliphatic 1,3-diketones with triethyl orthoformate afforded a number of β-ethoxy enones. Their reactions with o-phenylenediamine gave novel perfluoroalkyl-containing tridentate β-amino enones and tetradentate bis(β-amino enones) in high yields.

Simultaneous determination of aliphatic acids and aldehydes in aqueous media by reaction gas chromatography

A procedure is developed for the gas chromatographic determination of lower aldehydes as dibutoxyalkanes and carboxylic acids as butyl esters by the reaction with tributyl borate in an aqueous medium. Derivatization conditions were optimized. The procedure was used to determine side products in glyoxal synthesized by the catalytic oxidation of ethylene glycol.

Determination of glycols in glycol-containing oligomers using gas-liquid reaction chromatography

A method is proposed for the gas-chromatographic determination of glycols as bis(diethoxyphosphoryl) alkanes formed by the Atherton–Todd reaction with diethyl phosphite. Gas-chromatographic and mass-spectrometric characteristics of the derivatives obtained are studied. Conditions of the phosphorylation reaction are optimized. The method is applied to the determination of the residual amounts of glycols in oligomeric glycol-o-phthalates.

Synthesis, structure and complexation of the fluorinated 1,3-enaminoketones containing at the nitrogen atom substituents with a terminal C≡C bond

The reaction of fluorinated lithium 1,3-diketonates with propargylamine hydrochloride and 1,1,1-trifluorpentane-2,4-dione or 1,1,1-trifluoro-4-methoxypent-3-en-2-one with propargylamine and 3-aminophenylacetylene were performed to obtain fluorinated 1,3-enaminones containing at a nitrogen atom substituents with terminal C≡C bonds: (Z)-1,1,1-trifluoro-4-(2-propynylamino)-3-pentene-2-one, (Z)-1,1,2,2-tetrafluoro-5-(2-propynylamino)-4-hexen-3-one, and 4-(3-ethynylphenylamino)-1,1,1-trifluoropentyl-3-en-2-one. Reactions of 4-(3-ethynyl-phenylamino)-1,1,1-trifluoro-pentyl-3-en-2-one with Cu(II) acetate or nanosized powder of copper or its oxides led to the respective chelate complex. The structure of (Z)-1,1,2,2-tetrafluoro-5-(2-propynylamino)-4-hexen-3-one and a copper complex of 4-(3-etinilphenylamino)-1,1,1-trifluoropenta-3-en-2-one was determined by XRD.