Olga N. Kazheva

Synthesis and Structure of 2-Ethoxy- and 2-Aminomethylidene- 3-fluoroalkyl-3-oxopropionates

Condensation of ethyl 3-polyfluoroalkyl-3-oxopropionates with excess triethyl orthoformate gave ethyl 3-polyfluoroalkyl-2-ethoxymethylidene-3-oxopropionates which reacted with primary aliphatic, aromatic, and heterocyclic amines to form ethyl 2-alkyl(aryl, hetaryl)aminomethylidene-3-polyfluoroalkyl-3-oxopropionates. According to the X-ray diffraction and IR data, the latter exist in the crystalline state as the corresponding E isomers, while in solution (NMR data), as mixtures of Z and E isomers. Condensation of ethyl 2-ethoxymethylidene-3-oxopropionates with secondary heterocyclic amines (morpholine and pyrrolidine) led to the formation of 2-morpholino(pyrrolidin-1-yl)methylidene-3-fluoroalkyl-3-oxopropionates which were shown to exist as Z isomers both in the crystalline state and in solution.

A Domino Reaction of α,β-Acetylenic γ-Hydroxy Nitriles with Arenecarboxylic Acids: An Unexpected Facile Shortcut to 4-Cyano-3(2H)-furanones

An unexpected facile domino reaction of alpha,beta-acetylenic gamma-hydroxy nitriles with arenecarboxylic acids (Et(3)N, MeCN, 20-25 degrees C, 48 h) affords 4-cyano-3(2H)-furanones in 67-86% yield. The reaction is triggered by the addition of an arenecarboxylic acid to a triple bond, followed by the domino reaction sequence: intramolecular transesterification-enol formation and Claisen condensation of the ketoacetonitrile tautomer with ester functional group.

Syntheses, structures, and electroconductivity of bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) and bis(methylenedithio)tetrathiafulvalene (BMDT-TTF) salts with cobalt 8,8′-dichloro-3,3′-bis(1,2-dicarbollide)

Radical cation salts of bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) and bis(methylenedithio)tetrathiafulvalene (BMDT-TTF) with the 8,8′-dichloro derivative of cobalt bis(1,2-dicarbollide) (BEDT-TTF)2[8,8′-Cl2-3,3′-Co(1,2-C2B9H10)2] (1) and (BMDT-TTF)4[8,8′-Cl2-3,3′-Co(1,2-C2B9H10)2] (2) were synthesized and their crystal structures and electrocon-ducting properties were determined. The synthesized radical cation salts are semiconductors with the conductivity σ293 = 1.5 and 2.0 Ohm−1 cm−1, respectively. A decrease in the size of the substituent in a series of (BEDT-TTF)2[8,8′-X2-3,3′-Co(1,2-C2B9H10)2] and (BMDT-TTF)4[8,8′-X2-3,3′-Co(1,2-C2B9H10)2] (X = I, Br, Cl) results in the compression of the anion sublattice of the crystal and compaction of the radical cation packing of the conducting layer, which, in turn, increases the conductivity of the crystals.

Crystal structure and molecular packing in a new organic semiconductor penta[bis(ethylenedithio)tetrathiafulvalene]-hexathiocyanatomononitratoyttrium(III)-ethanol

Abstract A new radical cation (ET)5[Y(NCS)6NO3]·C2H5OH salt was prepared by electrochemical oxidation of ET in a chlorobenzene–ethanol solution. Its crystal structure and conducting properties were examined. The salt has a layered crystal structure with a new type of molecular packing in the radical cation layer, which was called the ω-type. The observed electroconducting properties suggest that this salt is a semiconductor.

Novel packing type of ET radical cation layers in a new organic conductor (ET)5[Dy(NCS)6NO3]·C2H5OH with a metal-complex lanthanide anion

Abstract A new radical cation (ET) 5 [Dy(NCS) 6 NO 3 ]·C 2 H 5 OH salt was prepared by electrochemical oxidation of ET in a chlorobenzene–ethanol solution. Its crystal structure and conducting properties were examined. The salt has a layered crystal structure with a basically new packing type of the radical cation layer, which was called an ω-type. Resistance studies reveal a semiconducting nature of this salt.

Structure of some molecular conductors with rare-earth metal counter-anions

New radical cation salts(ET) 5 [M(NCS) 6 NO 3 ] C 2 H 5 OH (M = Dy, Y) were prepared. The salts have a layered structure with a new ω-type packing type of the ET molecules.

1,3-Dipolar Cycloaddition of 3-Phenylamino-5-phenylimino- 1,2,4-dithiazole to 1-Acyl-2-phenylacetylenes—A New Route to Functionalized 1,3-Thiazole Derivatives

Abstract3-Phenylamino-5-phenylimino-1,2,4-dithiazole reacted with 1-acyl-2-phenylacetylenes in ethanol or toluene on heating (78–80°C, 1 h) in chemo- and regioselective fashion to give previously unknown N-[5-acyl-3,4-diphenyl-1,3-thiazol-2(3H)-ylidene]-N′-phenylthioureas (yield 57–60%). The structure of N-[5-benzoyl-3,4-diphenyl-1,3-thiazol-2(3H)-ylidene]-N′-phenylthiourea was proved by X-ray analysis.

Geometric isomerism in the series of fluoroalkyl-containing 1,2,3-trione 2-arylhydrazones

According to the 1H, 13C, and 19F NMR data, fluoroalkyl-containing 1,2,3-trione 2-arylhydrazones in CDCl3 exist exclusively, while in (CD3)2CO preferentially, as isomers in which the acyl or aroyl group is involved in intramolecular hydrogen bond. The isomer structure was assigned on the basis of the chemical shifts of the carbonyl carbon atoms and fluorine atoms and carbon-fluorine spin-spin coupling constants JC-F. X-Ray diffraction data showed that 1,2,3-trione 2-arylhydrazones in crystal have the same structure as in CDCl3 solution. Quantum-chemical calculations were performed to rationalize predominant formation of 1,2,3-trione 2-arylhydrazone isomers with a free polyfluoroacyl group.

Synthesis, structure, and properties of a new bifunctional radical cation salt with ferracarborane anion: (BEDT-TTF)2[8,8´-Cl2-3,3´-Fe(1,2-C2B9H10)2]

A new radical cation salt of bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) with iron(III) bis(1,2-dicarbollide) 8,8´-dichloro derivatives, that is (BEDT-TTF)2[8,8´-Cl2-3,3´-Fe-(1,2-C2B9H10)2], was synthesized. Its electroconducting and magnetic characteristics were studied, molecular and crystal structures were determined. The electroconductivity of crystals at room temperature was σ293 ~5 Ω–1 cm–1, which is close to the corresponding value for the salt of cobalt bis(1,2-dicarbollide) dichloro derivative and is considerably higher than the electroconductivity of a similar salt of unsubstituted iron bis(1,2-dicarbollide). The measurements of magnetic susceptibility at 2—300 K showed that this salt is paramagnetic.

New approach to the synthesis of azauracils and azaisocytosines

A new procedure was developed for the synthesis of 6-phenyltetrazolo[1,5-b]triazin-7-one. Aza analogs of uracil and isocytosine were prepared by the tetrazole ring cleavage. It was demonstrated that these transformations can be used in the synthesis of anomalous nucleosides.