Structure of paniculamine,a new alkaloid fromAconitum paniculatum

From the roots of the cultivated plant Aconitum paniculatum Lam. we have isolated a new diterpene alkaloid of the denudatine type, which we have called paniculamine and have established its structure by x-ray structural analysis (diffractometer, CuK= radiation, 1729 reflections, direct method, R = O. 055).Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (3712) 89 14 75. Translated from Khimiya Prirodnylh Soedinenii, No. 2, pp. 277–282, March-April, 1995. Original article submitted November 15, 1994.     

Isolation of hispidin from a walnut-tree fungus and its antioxidant activity

An -styrylpyrone derivative — hispidin — has been isolated from a walnut-tree fungus. Its antioxidant activity has been studied inin vitro andin vivo experiments on animals of different ages.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. 1, pp. 34–37, January–February, 1996. Original article submitted November 3, 1995.     

Alkaloids of the Mongolian flora. III. Altaconitine — A new alkaloid from Aconitum altaicum

Aconitine, mesaconitine, and a new alkaloid, which has been called altaconitine, have been isolated from the total alkaloids of the epigeal part ofAconitum altaicum. Altaconitine has the structure of 8-acetoxy-14-benzoyloxy-2,3,13,-15-tetrahydroxy-1,6, 16-trimethoxy-4-methoxymethy-N-ethylaconitan, which was established on the basis of a study of IR, PMR,¹³C NMR, and mass spectra and by the x-ray structural method.Institute of Chemistry, Mongolian Peoples' Republic Academy of Sciences, Ulan-Bator. Institute of the Chemistry of Plant Substances of the Uzbekistan Republic of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 47–53, January–February, 1993.     

Germacranolide fromTanacetopsis mucronata

A sesquiterpene lactone of the germacrane series, mucrochin, has been isolated from the epigeal part ofTanacetopsis mucronata, and its structure has been studied by IR and mass spectral methods and PMR spectroscopy. It structure has been determined unambiguously by x-ray structural analysis as 5,6-dihydroxy-5α,6β,7α,8β(H)-germacra-1(10),4(15) 1(13)-trien-8,12-olide. A boat-chair conformation with a configuration of the₁D¹⁴ ₁₅D₅ type has been established. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 492–498, July–August, 1998.     

Features of colloidal disperse structure formation in petroleum bitumen

Temperature-modulated differential scanning calorimetry has been employed to analyze the structure-related thermal properties of petroleum bitumen. This method enables one to distinguish between “order–disorder” and glass transitions, thereby making it possible to monitor and identify structure-related phase transformations, the signals from which are invisible or overlapped in the thermograms of conventional differential scanning calorimetry. Bitumen has been shown to be a colloidal disperse system only under certain temperature–time conditions. Its dispersed phase may be represented by aggregates of two types with colloidal sizes. Saturated hydrocarbons form a solid crystalline phase in accordance with the regularities of first-order structural phase transitions and nucleation mechanism of phase separation. Asphaltenes and resins form a solid amorphous phase for a relatively long time as a result of a structural relaxation glass transition by the spinodal mechanism of phase separation.     

Synthesis and Structure of the Heterocyclic Phosphorus Containing Derivatives of [60] Fullerene

Abstract

Data on the structure of cycloadducts of organophosphorus dipolar reagents and fullerenes arc absent, to our knowledge. We died the reactions and the shucturc of cycloadducts of phosphorylated azidcs and nitrile oxide with [60]fullcrcnc. The cycloaddition of diphcnylphosphinic llzide to fullcrme has bcm determined to lead to the 1 -[(N-diphenylphosphoryl)amino]-2-hydroxy[6O]hllcrme (l), the mixhuc of phosphorylated aziridinofullcrcne (2) and derivative of fullerne (3) with one aziridine fragment and one aminohydmxy-fragment, or to product (4), depending on the conditions of don .     

Thermal and structural characterization of bitumen by modulated differential scanning calorimetry

Journal of Thermal Analysis and Calorimetry - This paper presents the results of investigation of model bitumens, prepared by mixing of individual fractions of bitumen (saturates, aromatics, waxes,...     

Synthesis and structure of Meisenheimer adducts in nucleophilic aromatic amination of 4,6-dinitrobenzofuroxan

Stable crystalline σ-complexes (Meisenheimer adducts) were isolated for the first time in the reactions of superelectrophilic 4,6-dinitrobenzofuroxan with dodecyl- and hexadecylamines, and their structure was determined by X-ray analysis.     

Circular dichroism of the products of the amination of lactones

The circular dichroism method has been used to study the products of the amination of sesquiterpene lactones containing α-methylene-γ-lactone groupings. Analysis of the results obtained has shown that in all the lactones considered the amination reaction takes place with the predominant formation of one of the possible stereochemical forms of the product of the addition of the amine to the exomethylene group of the lactone ring, namely, that having the 11S configuration.