Withasteroids ofPhysalis. V. A study of the1H and13C NMR spectra of the withasteroids visconolide and 28-hydroxywithaperuvin C

The PMR and¹³C NMR spectra of new withasteroids — visconolide and 28-hydroxywithaperuvin C, isolated fromPhysalis viscosa L. — have been investigated. A detailed analysis of the spectral characteristics obtained is given. For visconolide is proposed the structure of 4,12,17,28-pentahydroxy-1-oxo-5, 6-epoxy-22R-witha-2,24-dienolide, and for 28-hydroxywithaperuvin C that of 6,14,17,20R, 28-pentahydroxy-l-oxo-22R-witha-2, 4, 24-trienolide.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 657–663, September–October, 1985.     

Phytoecdysteroids of the plants of the genusSilene XV. Silenoside F — Brahuisterone 3-O-β-D-glucopyranoside fromSilene brahuica

A new brahuisterone glycoside — silenoside F — has been isolated from the epigeal part ofSilene brahuica Bois. (fam. Caryophyllaceae). Its structure has been established by an analysis of spectral characteristics: 3β,5,14α,22R,25-pentahydroxy-5β-cholest-6-one 3-O-β-D-glucopyranoside. Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (3712) 89 14 75. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 734–737, November–December, 1994.     

Structure of the sesquiterpene lactone tanacin

Summary From the leaves ofAtraphaxis pyrifolia Bge. we have isolated a new flavonoid glycoside. By chemical and spectroscopic investigations its structure has been established as 3,4,5,8-tetrahydroxy-7-methoxy-flavonol 3-O--L-rhamnopyranoside.S. M. Kirov Kazakh State University. Translated from Khimiya Prirodnykh Soedenenii, No. 2, pp. 136–140, March–April, 1975.     

Analysis of thermodynamic and kinetic stabilities in the thermal decomposition of the trinuclear μ-oxoacetates Fe 2 III MIIO(CH3OO)6(H2O)5, with M=Mn,Fe, Co or Ni

The thermal analysis of acetate clusters of general formula [Fe ₂ ^III M^IIO(CH₃COO)₆(H₂O)₃]·2H₂O, with M=Mn, Fe, Co or Ni, was performed in dynamic and quasi-isothermal regimes. The thermal decompositions of these compounds proceed in the interval 40–310° and consist of two endothermic and three exothermic stages. Dependence on the nature of the transition metal M is evidenced most explicitly in the parameters of the second stage, proceeding in the interval 103–170°. For this stage the sequences of thermodynamic stability and kinetic stability were established. The effect of the nature of the metal on the thermodynamic and kinetic parameters of the thermal decomposition processes involving the heteronuclear acetates was analyzed. Mechanisms for the first two stages of thermal decomposition are suggested.     

1H and13C NMR spectra of transformation products of gossypol in solutions

The complete cycle of the transformation of gossypol in solutions takes place in the measuring ampul of a NMR spectrometer. It has been established for the first time that, in methanol, gossypol is converted into stereoisomeric dilactol 15,15-dimethyl ethers which change into dianhydrogossypol in chloroform and back into gossypol in aqueous acetone. The¹H and¹³C NMR spectra of the main and intermediate products of the conversion of gossypol in the solvents mentioned have been studied in detail for the first time and a complete assignment of their resonance characteristics has been made. It has been shown that dianhydrogossypol is formed through intermediate stereoisomeric 15,15-dimethyl ethers of the dilactol form of gossypol.Institute of the Chemistry of Plant Substances, Uzbek SSR Academy of Sciences, Tashkent. V. I. Lenin Tashkent State University. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 166–177, March–April, 1990.     

Radiative annihilation of a lepton pair to form hadrons

The electromagnetic annililation of an e^–e⁺ pair to form hadrons, accompanied by the emission of a ray, is studied. A differential cross section is derived to describe the angular and energy distributions of the bremsstrahlung photons. The possibility of determining structure functions is studied. A five-quark model is used to calculate the circular polarization of the photon, P, and the transverse asymmetry coefficienta.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 25–29, December, 1981.     

Modification of the solubility of benzimidazole drugs on mechanical treatment with pectins

The change in the solubility of some benzimidazole drugs on their mechanical treatment with pectins has been investigated. It has been shown that the rate of desorption of a drug depends both on its structure and on the nature of the pectin.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent (IKhRV AN RUz), fax (3712) 89 1475. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 556–561, July–August, 1995. Original article submitted November 14, 1994.     

Possibility of measuring the coupling constants of heavy quarks

The electroweak asymmetries (the front-back angular asymmetry, the right-left asymmetry, the degree of longitudinal polarization of a quark, and the degree of circular polarization of a -ray) in the ordinary and radiative annihilation of an electron-positron pair into a pair of heavy quarks are analyzed in the standard Weinberg-Salam model. It is shown that these P-odd asymmetries are quite sensitive to the magnitude of the right-hand coupling constant of a quark.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 23–28, July, 1988.     

Weak neutral currents under photogeneration of hadrons on leptons

In this article we investigate the process of photogeneration of hadrons on leptons in the region of large imparted momenta (q² 1000 GeV²). Contributions of weak neutral currents and polarizations of initial and final electrons are taken into account, as well as the circular polarization of the photon. The asymmetry parameters A(^e) and A() and the spin correlation A(^e) are defined. The structure functions in the quark-parton model are found, and their dependence on x for q²=1000 GeV² is investigated. Graphs of the dependence of the asymmetry parameters on the square of imparted momentum q² and x are shown.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 8–14, October, 1987.