Pyrroloindoles. 16. Some electrophilic substitution reactions of 2,7-dicarbethoxy-1H,6H-pyrrolo[2,3-e]indoles

Electrophilic substitutions of 2,7-dicarbethoy-1H,6H-pyrrolo[2,3-e]indole (Friedel-Crafts acylation, nitration, bromination) take place both at position 3 of the indole ring and at positions 5 and 8 in the benzene ring.For communication 15 see [1].Iv. Dzhavakhishvili State University, Tbilisi 380028. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1197–1201, September, 1994. Original article submitted July 5, 1994.     

Glycosylation of cyclosieversiosides A and H

Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan. Tashkent Pharmaceutical Institute. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 621–622, July–August, 1993.     

Reaction of 5-haloanthra[1,9-cd]-6-isoxazolones with aziridine

The reaction of 5-haloanthra[1,9-cd]-6-isoxazolones with aziridine gave 5-aziri-dinoanthra[1,9-cd]-6-isoxazolones. The latter, upon reaction with acids, undergo cleavage of the aziridine ring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 885–888, July, 1984.     

TPD study of catalyst surface acidity

Acidity of catalyst surfaces of different nature such as -Al₂O₃, natural zeolite-clinoptilolite, and synthetic zeolite zeokar by adsorption of ammonia over a wide temperature range has been studied. Ammonia is adsorbed on the catalysts with different strengths, as evidenced by the presence of different types of acid sites.

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(-Al₂O₃, - , () . , , .

     

Extraction of uranium(VI) with non-plasticized and TBP-plasticized polyurethane foam sorbents loaded with dibenzoylmethane

Studies have shown that plots of the log of the distribution ratio versus pH for the distribution of uranium(VI) between non-plasticized and TBP-plasticized dibenzoylmethane-loaded polyurethane foams and dilute aqueous uranium(VI) solutions have a limiting slope of 0.6 at equilibrium pH values 4 and reach a maximum distribution constant at about pH 6.0. The results indicate that the extracted complex is a simple chelate, UO₂Me₂, where HMe denotes dibenzoylmethane. Plasticization of the foam with TBP has been found to significantly enhance the rate of extraction.     

Spectral and quantum-chemical study of some heteroanalogs of 1,4-bis(5-phenyl-2-azolyl)benzenes

The effect of structural changes in the molecules of thiophene and furan analogs of 1,4-bis(5-phenyl-2-azolyl)benzenes on their electronic spectra was studied by the MO LCAO method within the -electron approximation.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 817–821, June, 1991.     

Preparation and properties of high dispersity palladium catalysts

Preparation methods for monodisperse sols of palladium with 9, 15, 30 and 75 Å particles are suggested. It has been revealed that with decreasing size of palladium particles (d25 Å), the dissolved hydrogen species disappear. As a result, their behavior in dimethyl ethynyl carbinol hydrogenation is close to the platinum properties.

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9, 15, 30, 75 Å. , (d25 Å) , .

     

Hydrophobic effect for anionic dye - cationic surfactant interaction in aqueous and mixed solvent

Abstract

The interaction between anionic dyes [Reactive Orange 122 (R.O 122), Reactive Blue 19 (R.B 19), Reactive Violet 5 (R.V 5) and Acid Green 20 (A.G 20)] with cationic surfactant cetyltrimethylammoniun bromide (CTAB) has been investigated by spectrophotometry and conductance technique. The used dyes are characterized by tautomeric behavior which affects the mechanism of the interaction. Various parameters such as dye structure, surfactant composition, solvent composition, temperature and pH of the medium were studied. The spectral data were applied for calculating the binding constant between dye and surfactant (K_b), fraction of micellization (?_mic), and standard free energy change of binding (ΔG°_b) in 0,10,20 and 30 v/v % acetonitile (AN). Conductance technique was constructed to estimate the ion pairing constant (K_a) at different temperatures and v/v % AN. Thermodynamic parameters (ΔG°, ΔH° and ΔS°) for ion pair formation were evaluated. The role of hydrophobic and electrostatic effect on dye-surfactant interaction was discussed.     

Energy estimates of twinning processes in cubic single crystals

The role of twinning processes giving rise to the fragmentation and rotation of a structure caused by single-crystal deformation, as well as the joining of grains during the manufacturing of optical ceramics, is investigated. Models describing the twins in the single crystals under study, which are formed by rotating a cubic lattice about the threefold symmetry axis through an angle of 60°, are constructed. The twin formation energies are estimated.