4106
1992
deu
conferenceobject
1
2010-07-16
--
--
Structure and dynamics of free and metallated benzonaphthopyranones and -pyrans
First calculations of the structures of metal-free and complexed biaryl lactones and their confrrmation by X-ray crystaIlography, the search for the transition states of their heIimerization processes, and the spectroscopic determination of the heIimerization barriers of related cyclic ethers by DNMR are reported.
urn:nbn:de:bvb:20-opus-46858
4685
In: Selective reactions of metal activated molecules: proceedings of the symposium held in Würzburg, September 18 - 20, 1991 / Helmut Werner. - Braunschweig: Vieweg, 1992. - S. 179 - 182. - 3-528-06450-1.
Deutsches Urheberrecht
Christian Burschka
Gerhard Bringmann
Holger Busse
Stefan Guessregen
Bernd Schoener
Rainer Zagst
Chemie und zugeordnete Wissenschaften
open_access
Institut für Anorganische Chemie
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/files/4106/Burschka_Structure_dynamics.pdf
4070
1992
eng
article
1
2010-07-07
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Novel concepts in directed biaryl synthesis, IX: Synthesis and structure of benzonaphthopyranones, useful bridged model precursors for stereoselective biaryl syntheses
A practicable two-step procedure for the preparation of a series of lactone-type bridged biaryls 7 as favorable substrates for subsequent atropisomer-selective ring-opening reactions is described. Due to the efficiency of the coupling step, which tolerates even a telt·butyl group next to the biaryl axis and avoids problems of regioselectivity, a variety of differently substituted representatives is prepared. These cover a broad range of steric hindrance and thus molecular distortion. The structures are investigated mainly by NMR spectroscopy and X-ray diffraction, showing the lactones 7 to be helically distorted, depending on the size of the residues R.
urn:nbn:de:bvb:20-opus-46635
4663
In: Liebigs Annalen der Chemie (1992), 3, S. 225 - 232.
Deutsches Urheberrecht
Gerhard Bringmann
Thomas Hartung
Lothar Goebel
Olaf Schupp
Christian L. J. Ewers
Bernd Schoener
Rainer Zagst
Karl Peters
Hans Georg Von Schnering
Christian Burschka
deu
swd
Chemie
Chemie und zugeordnete Wissenschaften
open_access
Institut für Anorganische Chemie
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/files/4070/Burschka_Biaryl_synthesis_9.pdf
3343
1991
eng
article
1
2009-11-13
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Acetogenic Isoquinoline Alkaloids. XXIII. Structure of the Naphthyl Isoquinoline Alkaloid Dioncophylline A
No abstract available
urn:nbn:de:bvb:20-opus-31331
3133
In: Acta Cryst. (1991) C47, S. 1703 - 1705.
Deutsches Urheberrecht
Gerhard Bringmann
Rainer Zagst
Bernd Schöner
Holger Busse
Martin Hemmerling
Christian Burschka
deu
swd
Chemie
Chemie und zugeordnete Wissenschaften
open_access
Institut für Anorganische Chemie
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/files/3343/Burschka_Acetogenic.pdf
4492
1992
eng
article
1
2010-12-13
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+/- Dioncophyllacine A, a naphthylisoquinoline alkaloid with a 4-methoxy substituent from the leaves of Triphyophyllum peltatum
The isolation and structure elucidation of rac-dioncophyllacine A from the leaves of Triphyophyllun peltatum, is described. Unlike all other naphthylisoquinoline alkaloids, this fully dehydrogenated representative has an additional methoxy group at C-4, the position of which is deduced from NOE results. Dioncophyllacine A has a 7,1' site of the biaryl axis, as in dioncophylline A. Its constitution is confirmed by an X-ray structure analysis, which shows that the crystalline form of this new alkaloid is racemic.
urn:nbn:de:bvb:20-opus-31873
3187
In: Phytochemistry (1992) 31, 11, S. 4015 - 18.
Deutsches Urheberrecht
Gerhard Bringmann
Thomas Ortmann
Rainer Zagst
Bernd Schoener
Laurent Ake Assi
Christian Burschka
deu
swd
Dioncophyllaceae
eng
uncontrolled
Triphyophyllum peltaturn
eng
uncontrolled
Dioncophyllaceae leaves
eng
uncontrolled
(± )-dioncophyllacine A
eng
uncontrolled
naphthylisoquinoline alkaloids
eng
uncontrolled
structure elucidation
Chemie und zugeordnete Wissenschaften
open_access
Institut für Anorganische Chemie
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/files/4492/Burschka_Dioncophyllacine.pdf