Berberis alkaloids. XV. Structure of bargustanine

Bargustanine (I), belonging to a new type of isoquinoline alkaloids, has been isolated from the phenolic fraction of the total alkaloids from the roots ofBerberis vulgaris L. Its structure has been established by chemical and spectral methods.Institute of Chemistry of Plant Substances, Uzbekistan Republic Academy of Sciences, Tashkent. Andizhan State Medical Institute. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 44–47, January–February, 1993.     

A five-coordinate complex of copper chloride with 2-amino-5-ethyl-1,3,4-thiadiazole

A complex of Cu(II) chloride with 2-amino-5-ethyl-1,3,4-thiadiazole (AET) was prepared, and its structure was studied by IR spectroscopy and single crystal X-ray diffraction. The complex has the composition CuCl₂(AET)₄. The coordination sphere of the copper atom includes four molecules of the heterocyclic ligand coordinated via N atoms of thiadiazole rings and one of Cl^? anions; the second Cl^? anion is in the outer sphere.     

Berberis alkaloids. XVII. Investigation of the alkaloids of Berberis heteropoda

The alkaloid composition of young shoots and leaves ofBerberis heteropoda Schrenk has been studied. In addition to known alkaloids, two new ones have been isolated — N-methyldihydroberberine and 8-oxoberberrubine, the structures of which were established by chemical transformations and a study of spectral properties. Of known alkaloids, berbamunine, aromoline, glaucine, thalicmidine, isocorydine, and reticuline have been found in this plant for the first time. Pseudopalmitine and laudanosine have been found for the first time in plants of the genusBerberis.Andizhan State Medical Institute. Institute of the Chemistry of Plant Substances of Uzbek Republic Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 53–59, January–February, 1993.     

Nanostructured Crystals of Fluorite Phases Sr1 – xRxF2 + x (R Are Rare-Earth Elements) and Their Ordering. 14: Concentration Dependence of the Defect Structure of Nonstoichiometric Phases Sr1 – xNdxF2 + x As Grown (x = 0.10, 0.25, 0.40, 0.50)

Crystallography Reports - The defect structure of as grown Sr1 – xNdxF2 + x (x = 0.10–0.50) crystals grown from a melt by...     

Anisotropy of Ionic Conductivity of TbF3 Crystals

Crystallography Reports - Temperature measurements (in the range of 375–830 K) of the ionic conductivity of terbium trifluoride single crystals (structure type β-YF3) along three...     

Synthesis and electrocatalytic activity of palladium nanoparticles on porous silicon

Palladium was combined with porous silicon into catalytically active functional electrode nanocomposites. Palladium nanoparticles were examined by transmission electron microscopy and atomic force microscopy; their catalytic activity was estimated using cyclic voltammetry.     

Flow oscillations in radial expansion of an inhomogeneous plasma layer

The cylindrically symmetric radial evolution of an inhomogeneous plasma layer expanding into vacuum is investigated nonperturbatively by first determining the spatial structure of the plasma flow structure. The evolution is then governed by a set of ordinary differential equations. The effect of the plasma inhomogeneity on the nonlinear coupling among the electron and ion flow components and oscillations is investigated.     

synthesis and properties of β-brominated metal complexes of meso-triphenylcorrole

Spectral properties and chemical stability of Mn(III), Mn(IV), Fe(III), Fe(IV), and Cu(III) complexes of β-octabromotriphenylcorrole [(β-Br)₈(ms-Ph)₃Cor], synthesized from β-unsubstituted compounds by their reaction with molecular bromine, were studied. Cyclic voltammetry, electron microscopy, and X-ray spectral microanalysis were used to obtain electrochemical characteristics of metal corroles M(β-Br)₈(ms-Ph)₃Cor and gain insight into the surface texture of active catalysts on the basis of metal corroles. The electron-acceptor β-bromine substitution in the MCor macrocycle shifts the equilibrium in electron-donor solvents to lower oxidation states of the metals and also stabilizes manganese and destabilizes copper complexes in the protondonor medium HOAc-H₂SO₄. The electrocatalytic activity of the complexes in the reduction of molecular oxygen depends on the nature of the ligand and increases in the order Mn ≤ Cu ? Fe in the case of β-octabrominated macrocycles. The character of distribution of active centers on the surface of the catalysts was established for the first time.     

Nanostructured Crystals of Fluorite Phases Sr1 – xRxF2 + x (R Are Rare-Earth Elements) and Their Ordering. 13: Crystal Structure of SrF2 and Concentration Dependence of the Defect Structure of Nonstoichiometric Phase Sr1 – xLaxF2 + x As Grown (x = 0.11, 0.20, 0.32, 0.37, 0.47)

Crystallography Reports - The defect structure of as-grown SrF2 and nonstoichiometric phases Sr1 – xLaxF2 + x (x = 0.11, 0.20, 0.32, 0.37, 0.47) single...     

Thermal diffusion zincing/aluminizing of steels and alloys under mechanical activation of sample surfaces

Possibility of producing zinc-aluminide coatings by thermal diffusion impregnation of steels under mechanical activation of the surface of samples in a rotating reactor was analyzed.