The photoconversion R-CH3 → R-CHO in indazole derivatives

The UV irradiation of 1-(p-nitrophenyl)-3-methyl-indazole leads to the formation of the corresponding 3-formyl derivative as product of the photooxidation R-CH₃ → R-CHO. This method was applied to a series of substituted indazoles and the same reaction was observed with methyl groups attached to the pyrazole and to the benzene ring of the indazole.     

Analytical aspects of some organic acids

Summary A direct titrimetric method for the estimation of iron(III) has been developed, which involves the adjustment of concentration of iron(III) andPh, dilution, addition of 1 ml of 2% indicator solution and titration with EDTA (30° to 35° C). It is based on the fact that the iron(III) forms a blue coloured complex which is destroyed at the 11 molar ratio making the end-point of the titration. Quantity of iron(III) as small as 23.2 mg can be titrated accurately when present in a volume of 100 ml. Study of interferences revealed that quite a number of elements like Be²⁺, Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺, UO₂ ²⁺ and Mn²⁺ does not interfere, whereas much interference is caused by Cu²⁺, Zn²⁺, Pb²⁺, Fe²⁺, Co²⁺, Ni²⁺, ZrO²⁺, V0²⁺, Al³⁺, Cr³⁺, Ti⁴⁺, Ce⁴⁺ and Th⁴⁺. The method proposed for iron(III) is selective and should be of considerable use in many cases.Part III: See Z. analyt. Chem. 167, 332 (1959).     

Kinetics and mechanism of oxidation of substituted benzaldehydes by quinolinium fluorochromate

The kinetics of oxidation of a number of meta- and para-substituted benzaldehydes by quinolinium fluorochromate, QFC has been studied in aqueous acetic acid medium in the presence of acid. The products of oxidation are the corresponding benzoic acids. The reaction is first order each in substrate, QFC and HClO₄. Electron-withdrawing substituents increase the rate, while electron-releasing substituents decrease it and the rate data obey Hammett's relationship. The reaction constant for the oxidation has a value of 1.16±0.07 at 30°C. The activation enthalpies and entropies are calculated and the possible mechanism for oxidation is discussed.     

Investigation on structure and morphology of the thermally treated glassy alloy (Fe,Cr)80(P,C,Si)20 by means of ESCA and SEM/EDXA

Metallic glass ribbons of the chemical composition (Fe,Cr)₈₀(P,C,Si)₂₀ have been thermally treated in the region between 530 and 980°C for 72 h. The SEM/EDXA investigations indicate that a phase transformation takes place between 575 and 980°C in a surface layer of 5 m thickness. Thus, a Cr-rich phase occurs between 760 and 800°C which is converted into an open-pore system between 850 and 900°C. The oxidation process reaches its maximum at 760°C. The ESCA spectra of the material in the as received state and of the thermally treated samples indicate that different oxygen species are formed within the analysed surface layer of 10 nm. The oxygen of the original material is incorporated as hydroxyl groups in species such as FeO(OH) and CrO(OH). After thermal treating the hydroxyl content decreases and the oxide content increases. Species of Si exist in the surface layer as SiO_x-like compounds (peak at BE=102.0 eV). A majority phase of transition metal phosphide species is coexisting with oxidised phosphate species.     

Wannier-Stark effect on surface states

A recursive Green-function (RGF) technique is used to study the surface states of an electrified solid. The concatenating nature of the method leads to a continued-fraction form of the RGF, which can be expressed as a ratio of Bessel functions. The surface density of states (SDOS), derived from the RGF, reveals a quasi-Stark-ladder distribution of the energy levels at the surface atom. The dependence of the SDOS on the applied field and surface perturbation parameters is discussed.     

Electrochemical extraction of alkaloids from ephedra herbage

The process of extracting ephedra herbage in a constant electric field has been studied. It has been shown that the application of an electric field considerably accelerates the isolation of the alkaloid molecules from the cellulose of the plant raw material. The main kinetic characteristics of the electroextraction of the total alkaloids as functions of various factors have been obtained.Institute of Organic Synthesis and Coal Chemistry, Kazakh SSR Academy of Sciences, Karaganda. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 862–864, November–December, 1987.     

Effect of adsorption of vapours on the electrical conductivity of some polyene semiconductors: adsorption and desorption kinetics

The change in semiconductive properties of β-apo-8′-carotenal, astacene and methyl bixin on adsorption of various vapours on the crystallite surfaces has been studied at a constant sample temperature. The adsorption of vapours enhances the semiconductivity of the polyenes appreciably. This enhancement depends on the chemical nature and also on the pressure of the adsorbed vapour. The adsorption and desorption kinetics follow the modified Roginsky-Zeldovich relation. A two stage desorption process, the first stage of which gives a Lennard-Jones potential energy curve and is followed by a rate-determining transition over a potential energy barrier to the second stage of adsorption forming weakly bound complexes between the vapour molecules and the polyene crystallites, can explain satisfactorily the experimentally observed kinetic data.     

Sesquiterpene lactones from Artemisia caucasica

Conclusions 1. Two sesquiterpene lactones have been isolated from the epigeal green part ofArtemisia caucasica Willd.: one with the composition C₁₅H₁₈O₅·H₂O, which has been called grossmisin, and one with the composition C₁₅H₁₈O₅, identified as rutifolin. Structure (I) has been proposed for grossmisin.2. The structure of anhydroaustricin has been reviewed. Structure (II) is proposed for it.Pyatigorsk Pharmaceutical Institute. All-Union Scientific-Research Institute for Medicinal Plants. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 741–744, November–December, 1971.     

Triterpene glycosides ofHerniaria glabra. I

Conclusions FromHerniaria glabra L. two triterpene glycosides, glabrosides B and C, have been isolated. We have shown that the first is the -D-glucopyranosyl-(16)--D-glucopyranoside, and the second is the Khimiya Prirodnykh Soedinenii, Vol. 6, No. 3, pp. 307–311, 1970     

ESR study of free radicals chemically generated at high pressure

Free radicals generated by the thermal decomposition of benzoyl peroxide in polyacrylnitrile were studied by the ESR method at 700 MPa between 100 and 130°C. The formation and decay of macroradicals were investigated and the mechanism of macroradical generation is discussed.

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700 MPa 100 130°C. .