Sesquiterpene Lactones of Ambrosia artemisiifolia L. and Ambrosia trifida L. Species

1992 ◽  
Vol 57 (5) ◽  
pp. 1092-1102 ◽  
Author(s):  
Ełżbieta Błoszyk ◽  
Urszula Rychłewska ◽  
Beata Szczepanska ◽  
Miloš Buděšínský ◽  
Bohdan Drożdż ◽  
...  
Keyword(s):  
Structural Analysis ◽  
Aerial Part ◽  
Sesquiterpene Lactones ◽  
Ambrosia Artemisiifolia ◽  
Cd Spectra ◽  
Ambrosia Trifida ◽  
X Ray ◽  
Aerial Parts ◽  
Full Structure

In addition to the already described peruvin (I), two further lactones, 3α-hydroxy-11αH,13-dihydrodamsin (II) and, 3α-acetoxy-11αH,13-dihydrodamsin (III), were isolated from aerial parts of species Ambrosia artemisiifolia L. The full structure of these lactones was derived from their NMR and CD spectra and the X-ray structural analysis of compound III. In the aerial part of Ambrosia trifida L. species coronopilin (V) and ivoxanthin (VI) were also identified.

Sesquiterpene lactones of Cephalophora aromatica (HOOK.) SCHRADER and their deterrent activity. The stereostructure of geigerinin

1989 ◽  
Vol 54 (7) ◽  
pp. 1903-1918 ◽  
Author(s):  
Ełżbieta Błoszyk ◽  
Aleksandra Dudek ◽  
Zofia Kosturkiewicz ◽  
Urszula Rychłewska ◽  
Włodzimierz M. Daniewski ◽  
...  
Keyword(s):  
Absolute Configuration ◽  
Sesquiterpene Lactones ◽  
Cd Spectra ◽  
Antifeedant Activity ◽  
Crop Pests ◽  
X Ray ◽  
Main Crop ◽  
Deterrent Activity

From species Cephalophora aromatica (HOOK.) SCHRADER the authors isolated a series of previously described sesquiterpene lactones I-V and newly the lactone geigerinin (VI). Its structure was confirmed by X-ray analysis and its absolute configuration was determined on the basis of the CD spectra of its complex with Pr(thd)3. The lactones I-VII were tested for antifeedant activity against main crop pests.

RNA polymerase: Preparation and structural analysis of helical polymers

1984 ◽  
Vol 42 ◽  
pp. 152-153
Author(s):  
E. Loren Buhle ◽  
Pamela Rew ◽  
Ueli Aebi
Keyword(s):  
Structural Analysis ◽  
Rna Polymerase ◽  
Molecular Level ◽  
X Ray Diffraction ◽  
Helical Polymers ◽  
X Ray ◽  
E Coli ◽  
The Past ◽  
Ordered Arrays ◽  
Low Ionic Strength

While DNA-dependent RNA polymerase represents one of the key enzymes involved in transcription and ultimately in gene expression in procaryotic and eucaryotic cells, little progress has been made towards elucidation of its 3-D structure at the molecular level over the past few years. This is mainly because to date no 3-D crystals suitable for X-ray diffraction analysis have been obtained with this rather large (MW ~500 kd) multi-subunit (α2ββ'ζ). As an alternative, we have been trying to form ordered arrays of RNA polymerase from E. coli suitable for structural analysis in the electron microscope combined with image processing. Here we report about helical polymers induced from holoenzyme (α2ββ'ζ) at low ionic strength with 5-7 mM MnCl2 (see Fig. 1a). The presence of the ζ-subunit (MW 86 kd) is required to form these polymers, since the core enzyme (α2ββ') does fail to assemble into such structures under these conditions.

Sesquiterpene Lactones and Flavonoids from the aerial parts of Anthemis melanolepis L

Planta Medica ◽  
2006 ◽  
Vol 72 (11) ◽  
Author(s):  
H Skaltsa ◽  
V Saroglou ◽  
Z Kypriotakis
Keyword(s):  
Sesquiterpene Lactones ◽  
Aerial Parts

Sesquiterpene lactones from the aerial parts of Anthemis melanolepis L

Planta Medica ◽  
2007 ◽  
Vol 73 (09) ◽  
Author(s):  
V Saroglou ◽  
A Karioti ◽  
H Skaltsa
Keyword(s):  
Sesquiterpene Lactones ◽  
Aerial Parts

The crystal and molecular structure of tris(pentamethylenedithiocarbamate) chromium(III)-chloroform (1 : 2)

1981 ◽  
Vol 46 (1) ◽  
pp. 6-19 ◽  
Author(s):  
Viktor Kettman ◽  
Ján Garaj ◽  
Jaroslav Majer
Keyword(s):  
Molecular Structure ◽  
Structural Analysis ◽  
Crystal And Molecular Structure ◽  
Analysis Method ◽  
Complex Molecules ◽  
Coordination Polyhedra ◽  
X Ray ◽  
Cell Dimensions ◽  
Crustal Density ◽  
Unit Cell Dimensions

The crystal and molecular structure of [Cr(S2CN(CH2)5)3].2 CHCl3 was found by the X-ray structural analysis method. The value R 0.090 was found for 1 131 observed independent reflections. The substance crystallizes in a space group of symmetry P212121 with the following unit cell dimensions: a = 0.8675 (6), b = 1.815(2), c = 2.155(3) nm. The experimentally observed crustal density was 1.48 Mgm-3 and the value calculated for Z = 4 was 1.51 Mgm-3. The CrS6 coordination polyhedron has the shape of a trigonally distorted octahedron, where the D3 symmetry is a approximately retained. The degree of trigonal distortion expressed as the projection of the chelate S-Cr-S angle onto the plane perpendicular to the C3 pseudo axis is Φ = 41.7° (Φ = 60° for an octahedron). The skeleton of the structure formed by the complex molecules contains channels filled with chloroform molecules. The specific type of complex-chloroform interaction consists of the formation of hydrogen bonds of the chloroform protons with the fully occupied pπ-orbitals of the sulphur atoms in the coordination polyhedra. The low stability and crystal decomposition can be explained by loss of chloroform from the channels.

Reactivity of Sodium Hexaethyl-2,4-dicarba-nido-hexaborate(1-)

1999 ◽  
Vol 64 (6) ◽  
pp. 977-985 ◽  
Author(s):  
Bernd Wrackmeyer ◽  
Hans-Jörg Schanz ◽  
Wolfgang Milius ◽  
Catherine McCammon
Keyword(s):  
Mössbauer Spectroscopy ◽  
Nmr Spectroscopy ◽  
Structural Analysis ◽  
Hydrogen Atom ◽  
Mossbauer Spectroscopy ◽  
Sandwich Complex ◽  
X Ray ◽  
Bromo Derivative ◽  
Boron Tribromide ◽  
C Nmr

Sodium hexaethyl-2,4-dicarba-nido-hexaborate(1-) (6), available from hexaethyl-2,4-dicarba- nido-hexaborane(8) (4) by deprotonation, reacts with deuterated methanol, CD3OD, to give back 4 without H/D exchange of the B-H-B hydrogen atom. The reaction of 6 with diethylboron chloride, Et2BCl, affords hexaethyl-2,4-dicarba-closo-hexaborane(6) (7), the first example of a peralkylated carborane of this type. In contrast, the reaction of 6 with boron tribromide, BBr3, leads mainly to 2,3,4,5,6,7-hexaethyl-2,4-dicarba-closo-heptaborane(7) (8), together with the corresponding 1-bromo derivative (9) and the closo-carborane 7 as side products. The reaction of two equivalents of 6 with FeCl2 gives the air-stable sandwich complex bis[hexaethyl-2,4-dicarba-nido-hexaborate(1-)]iron 10 which was characterised by X-ray structural analysis. All products were characterised by 1H, 11B and 13C NMR spectroscopy, and 57Fe Mössbauer spectroscopy was used to study 10.

scholarly journals X-Ray Structural Analysis of Molten KF–KX(X=Cl, Br, and I) Systems

1987 ◽  
Vol 1987-7 (1) ◽  
pp. 165-174
Author(s):  
Yoshihiro OKAMOTO
Keyword(s):  
Structural Analysis ◽  
X Ray

scholarly journals Light-induced [2 + 2] Cycloaddition of 6-Methoxy-2-naphthonitrile to 2-Chloroacrylonitrile

1999 ◽  
Vol 23 (1) ◽  
pp. xiv-xiv
Author(s):  
Nader A. Al-Jalal ◽  
Robin G. Pritchard ◽  
Charles A. McAuliffe
Keyword(s):  
Structural Analysis ◽  
X Ray

6-Methoxy-2-naphthonitrile undergoes photocycloaddition to 2-chloroacrylonitrile to give [2 + 2] cyclobutane adducts (1a and 1b), the structure of one of which (1a) has been unambiguously confirmed by an X-ray structural analysis.

Competition between Ambrosia artemisiifolia and Ambrosia trifida : Is there a threat of a stronger competitor?

Weed Research ◽  
2021 ◽  
Author(s):  
Aleksandra Savić ◽  
Mostafa Oveisi ◽  
Dragana Božić ◽  
Danijela Pavlović ◽  
Markola Saulić ◽  
...  
Keyword(s):  
Ambrosia Artemisiifolia ◽  
Ambrosia Trifida
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