Neue (Hetero-)Triarylmethan-Derivate

The following groups of title substances according to general formula I where prepared: substituted , -diphenyl-2-thenyl-derivatives (mainly of heterocyclic secondary amines), chlorinated -phenyl--(2-thienyl)-4-pyridinemethanoles and substituted (mainly chlorinated) tri- and tetraphenylmethanes.     

Mass spectrometric study of linear and angular pyrrolodibenzofurans,pyrrolodibenzothiophenes, and pyrrolocarbazoles

The analysis of the mass spectra of unsubstituted pyrrolodibenzofurans and -carboxy- and -carbethoxypyrrolodibenzofurans, -carboxy- and -carbethoxy-pyrrolodibenzothiophenes, and -carbethoxypyrrolocarbazoles, in which the pyrrole ring is fused to faces a, b, or c, permits finding the differences in the relative intensities of the peaks of their fragmentary ions due to the presence of additional free reactions in these structures or different internal stabilization of the fragmentary ions. The mass spectral characteristics which make it possible to identify the type of fusion of the pyrrole ring by comparison of the mass spectra of pairs of isomers are reported.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1506–1510, November, 1985.     

Kinetics of Gold Electrodeposition from Cyanide Electrolytes at a Monitored Surface Coverage by Thallium Atoms

A procedure for measuring kinetic parameters of gold electrodeposition in the presence of catalytically active thallium(I) ions while monitoring the coverage of the gold surface by thallium adatoms, , is described. The procedure accounts for the duration of contact between a freshly renewed surface of gold and a thallium-containing solution and assumes that the incorporation rate of thallium adatoms is proportional to and the current density of gold electrodeposition. At = const, kinetic dependences correspond to the Tafel equation. Values of and i ₀ increase with . At = 0.3, 0.6 and i ₀ 3 × 10^–4 A cm^–2, which conforms to values calculated from anodic curves obtained in similar conditions.     

Kinetics and mechanism of OsO4 catalyzed oxidation of maleic, fumaric, cinnamic and acrylic acids by acid bromate

The title reactions are zero order in bromate, first order in both substrate and catalyst. The order of reactivity is cinnamic acid>acrylic acid>fumaric acid>maleic acid. A plausible mechanism is discussed.

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, . : > > > . .

     

Circular Dichroism Spectra of 5- and 7-Bromo-6-ketosteroids

Circulardichroismspectra of 5- and 7-bromo-6-ketosteroidsof the cholestane and stigmastane serieswere studied. A negative Cotton effect corresponding to the n-* -transition of the ketone was observed in the CD spectra of 5-bromo-6-ketosteroids at 300 nm. The analogous Cotton effect was positive in CD spectra of 7-bromo-6-ketosteroids.     

Chemistry of heteroanalogs of isoflavones

3-Hetaryl-7-methoxychromones were obtained by reaction of -(5-ethoxycarbonyl-2-furyl)-, -(2-benzofuryl)-, and -(2-methoxy-carbonyl-5-benzofuryl)-2-hydroxy-4-methoxyacetophenones with methyl formate or ethyl orthoformate, and 3-hetaryl-4-hydroxy-7-methoxy-coumarins were obtained by reaction of the same compounds with diethyl carbonate. Methods for the synthesis of 3-hetaryl-7-hydroxy-chromones from -furyl- and -benzofuryl-substituted, 2,4-dihydroxyacetophenones were investigated.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 174–179, February, 1975.     

Effect of vanadium content on the character of acidic sites on V2O5/Al2O3 catalysts

By IR spectroscopy and TPD the effect of vanadium content on the relative proportion of strongly acidic sites of V₂O₅/Al₂O₃ catalyst was studied.

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- - V₂O₅/Al₂O₃.

     

Synthesis and transformations of the 20-substituted derivatives of 16α,17α-epoxy-5α-pregnane-3Β,21-diol-20-ones

A new and more effective sequence of reactions is proposed for the production of 16,17-isopropylidenedioxy-5-pregnane-3,21-diol-20-one. It uses methods previously unused for 5-H-steroids and involves 21-hydroxylation of 16,17-epoxy-5-pregnan-3-ol-20-one with diacetoxyiodobenzene and cis-opening of the obtained 21-hydroxy-16,17-epoxy-5-pregnane-3,21-diol-20-one by acetic acid in the presence of epoxycarbonylhydrazine, followed by condensation of the obtained product with acetone.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1185–1188, May, 1991.