Structure of laserolide and isolaserolide: Revision of constitution and determination of relative and absolute configuration

1985 ◽  
Vol 50 (8) ◽  
pp. 1878-1887 ◽  
Author(s):  
Miroslav Holub ◽  
Miloš Buděšínský ◽  
Zdenka Smítalová ◽  
David Šaman ◽  
Urszula Rychłewska
Keyword(s):  
Diffraction Analysis ◽  
Absolute Configuration ◽  
Cd Spectroscopy ◽  
X Ray Diffraction ◽  
Physical Methods ◽  
X Ray

The position of the ester groups in sesquiterpenic lactones laserolide (I) and isolaserolide (II) has been revised and its relative and absolute configuration determined by chemical and physical methods (NMR and CD spectroscopy). The structure I was confirmed by X-ray diffraction analysis. Laserolide (I) is the first germacranolide found in the Umbelliferae family, isolaserolide (II) is the first representative of new stereostructural group of elemanolides - 5βH,6αH,7αH,10αCH3-elema-1,3-dien-6,12-olides.

scholarly journals Determination of the absolute configuration of (+)-neopentyl-1-d alcohol by neutron and x-ray diffraction analysis.

1994 ◽  
Vol 91 (26) ◽  
pp. 12872-12876 ◽  
Author(s):  
H. S. Yuan ◽  
R. C. Stevens ◽  
R. Bau ◽  
H. S. Mosher ◽  
T. F. Koetzle
Keyword(s):  
Diffraction Analysis ◽  
Absolute Configuration ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Absolute

Sesquiterpenic lactones of the Inula caspica BLUME species

1990 ◽  
Vol 55 (6) ◽  
pp. 1568-1579 ◽  
Author(s):  
Sergazy M. Adekenov ◽  
Miloš Buděšínský ◽  
Metram A. Abdikalikov ◽  
Coblandy M. Turdybekov ◽  
David Šaman ◽  
...  
Keyword(s):  
Absolute Configuration ◽  
Cd Spectroscopy ◽  
X Ray Diffraction ◽  
Relative Configuration ◽  
X Ray

From Inula caspica BLUME (Compositae) were isolated 3β-hydroxy-2α-senecioyloxyisoalantolactone (I), whose structure was confirmed by X-ray diffraction and completed by determination of its absolute configuration, and britannin (II) whose relative configuration was determined by X-ray diffraction and absolute configuration by CD spectroscopy.

Synthesis of 4-(3-coumarinyl)-3-benzyl-4-thiazolin-2-one 4-methylbenzylidenehydrazone and determination of the isomeric structure by X-ray analysis

2003 ◽  
Vol 218 (12) ◽  
Author(s):  
Süheyla Özbey ◽  
Nilgün Karalı ◽  
Aysel Gürsoy
Keyword(s):  
Single Crystal ◽  
Diffraction Analysis ◽  
Spectral Data ◽  
X Ray Diffraction ◽  
X Ray ◽  
Isomeric Structure ◽  
Elemental Analyses

AbstractIn this study 4-(3-coumarinyl)-3-benzyl-4-thi azolin-2-one 4-methylbenzylidenehydrazone 3 was synthesised. An independent proof of the thiazolylhydrazone structure of 3 was achieved by single crystal X-ray diffraction analysis. Elemental analyses and spectral data (IR,

Alkaloids of Rauvolfia salicifolia GRISEB species

1982 ◽  
Vol 47 (11) ◽  
pp. 2912-2921 ◽  
Author(s):  
Patricia Sierra ◽  
Ladislav Novotný ◽  
Zdeněk Samek ◽  
Miloš Buděšínský ◽  
Ladislav Dolejš ◽  
...  
Keyword(s):  
Absolute Configuration ◽  
Cd Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Absolute

From the endemic Cuban species Rauvolfia salicifolia GRISEB nine alkaloids were isolated of which the following seven had been already described: (+)-ajmalidine (I), (-)-reserpiline (II), (-)-isoreserpiline (III), (-)-isocarapanaubine (IV), (-)-ajmalicine (V), (+)-vellosimine (VI), and (+)-yohimbine (VII). The structure of (-)-raucubaine (VIII) had been previously determined by X-ray diffraction and the structure of the alkaloid (-)-raucubainine (IX) was suggested on the basis of its conversion to (-)-raucubaine (VIII). The absolute configuration of (-)-raucubaine and (-)-raucubainine was elucidated by CD spectroscopy.

X-Ray Diffraction Analysis of Steel with Oxidised Surface Layer

2016 ◽  
Vol 368 ◽  
pp. 99-102
Author(s):  
Lukáš Zuzánek ◽  
Ondřej Řidký ◽  
Nikolaj Ganev ◽  
Kamil Kolařík
Keyword(s):  
Residual Stress ◽  
Surface Layer ◽  
Residual Stresses ◽  
Diffraction Analysis ◽  
Oxide Surface ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electrolytic Polishing ◽  
Small Depth

The basic principle of the X-ray diffraction analysis is based on the determination of components of residual stresses. They are determined on the basis of the change in the distance between atomic planes. The method is limited by a relatively small depth in which the X-ray beam penetrates into the analysed materials. For determination of residual stresses in the surface layer the X-ray diffraction and electrolytic polishing has to be combined. The article is deals with the determination of residual stress and real material structure of a laser-welded steel sample with an oxide surface layer. This surface layer is created during the rolling and it prevents the material from its corrosion. Before the X-ray diffraction analysis can be performed, this surface layer has to be removed. This surface layer cannot be removed with the help of electrolytic polishing and, therefore, it has to be removed mechanically. This mechanical procedure creates “technological” residual stress in the surface layer. This additional residual stress is removed by the electrolytic polishing in the depth between 20 and 80 μm. Finally, the real structure and residual stresses can be determined by using the X-ray diffraction techniques.

Structure determination of silica tantalum soda glasses by X-ray diffraction analysis

1995 ◽  
Vol 24 (1-3) ◽  
pp. 69-73 ◽  
Author(s):  
Manwar Hussain ◽  
Koichi Niihara ◽  
Koehi Fukumi
Keyword(s):  
Diffraction Analysis ◽  
Structure Determination ◽  
X Ray Diffraction ◽  
X Ray
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