Molecular and crystal structures of hemigossypolone and gossypolone

The results are given of an x-ray structural investigation of hemigossypolone isolated from the stems of a wiltinfected cotton plant and of gossypolone obtained by oxidizing gossypol.     

Alkylation of some 6-substituted purines under interphase catalysis conditions

The mixture of 9-, 3-, and 7-benzyl-6-substituted purines is formed in almost quantitative yield by the alkylation of 6-benzylamino-, 6-furfurylamino-, 6-methylthio-, and 6-chloropurine with benzyl halides in the biphasic system of the liquid-liquid or liquid-solid type in the presence of interphase catalysts (quaternary ammonium salts, 18-crown-6). The catalytic activity of the quaternary ammonium salts increases with the increase in the lipophilicity of the cation. Taking the alkylation of 6-benzylaminopurine as an example, the possibility of the application of triphasic catalysis in the alkylation reaction of purines is indicated. The alkylation of 6-substituted purines with isopropyl bromide proceeds regioselectively under the conditions of the interphase catalysis with the formation of the corresponding 9-isopropylpurines.For the preliminary communication, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 113–118, January, 1987.     

Phytoecdysteroids of plants of the genusSilene XIV. Brahuisterone fromSilene brahuica

A new ecdysteroid with the composition C₂₇H₄₄O₆ which has been called brahuisterone has been isolated from the epigeal part of the plantSilene brahuica Boiss. Its chemical and complete spatial structures have been established by spectral studies and the x-ray structural method (diffractometer, Cu-K radiations, 996 reflections, direct method, R=0.119).Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbekistan Republic, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 553–558, July–August, 1993.     

Organophosphorus derivatives of pentachlorobenzenethiol

Conclusions Nine new organophosphorus derivatives of pentachlorobenzenethiol were synthesized by the reactions of pentachlorobenzenesulfenvl chloride with dialkyl hydrogen phosphites and O,O-dialkyl hydrogen phosphorothioites.     

Synthesis of some mixed esters of thiophosphoric acid

Summary Six esters of O,O-dialkyl S-carbalkoxymethylphosphinic acids that have not been described in the literature were prepared and their structures demonstrated.     

High-Temperature Proton Conductors Based on Strontium and Barium Cerates: The Interphase Exchange and Diffusion of Oxygen

Kinetic parameters of interphase exchange of oxygen in high-temperature proton conductors BaCe_0.95Nd_0.05O_3- and SrCe_0.95Y_0.05O_3- are determined using an isotope exchange method in the temperature range 630-820°C at oxygen pressures of 2.7-13.3 gPa and diffusion coefficients for oxygen are calculated. Effective energies of activation of oxygen exchange and diffusion coefficients for oxygen are calculated. Dependence of exchange characteristics and the diffusion coefficients on the oxygen pressure in the gas phase is investigated. The oxygen exchange on the surface of studied oxides is shown to proceed only with the participation of oxygen of the oxides, which causes high rates of interphase exchange of oxygen of studied cerates of barium and strontium. It is shown that the obtained data satisfactorily agree with those found in the relevant literature.     

Description of the influence of intermolecular interaction on IR spectra's frequencies of simple dense fluids by Monte-Carlo simulation

The solvent-induced shift in IR spectrum of liquid CO is investigated by Monte-Carlo computer simulation. The intramolecular potential is Morse function, pair intermolecular potential includes short-range and dispertion parts. The calculated shift is 5 cm^?1 while the experimental value is 4 cm^?1.     

The investigation of natural compounds by HPLC. III. A study of sesquiterpene lactones of the guaiane type by microcolumn HPLC

Two comparable methods of microcolumn high-performance liquid chromatography (HPLC) have been developed for the sesquiterpene lactones leucomicin, matricarin, austricin, and anhydroaustricin and for the drug isolated from the epigeal part ofArtemisia leucodes.     

Mechanism of the reaction of quinobromide compounds with amines

Conclusions The mechanism of the reaction of quinobromide compounds with amines was studied by the kinetic method.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1212–1214, May, 1972.