Hindered rotation in a 1-alkylnapthalene. A dynamic nuclear magnetic resonance, difference nuclear overhauser enhancement, and molecular mechanics investigation of 1-neopentylnaphthalene. The t-butyl group as a probe of chirality

1984 ◽  
pp. 1053 ◽  
Author(s):  
J. E. Anderson ◽  
D. J. D. Barkel
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Molecular Mechanics ◽  
Hindered Rotation ◽  
Nuclear Overhauser Enhancement ◽  
Butyl Group ◽  
Nuclear Overhauser ◽  
Dynamic Nuclear Magnetic Resonance ◽  
Nuclear Magnetic

Major saponins from the starfish Asteriasforbesi. Complete structures by nuclear magnetic resonance methods

1987 ◽  
Vol 65 (6) ◽  
pp. 1384-1391 ◽  
Author(s):  
John A. Findlay ◽  
Mahesh Jaseja ◽  
D. Jean Burnell ◽  
Jean-Robert Brisson
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Sodium Sulfate ◽  
Nuclear Overhauser Enhancement ◽  
Nuclear Overhauser ◽  
Nuclear Magnetic

The structures of the two major saponins isolated from the starfish Asteriasforbesi have been deduced totally by nuclear magnetic resonance methods applied to the undegraded molecules. The structure of forbeside A, 6α-O-{β-D-galactopyranosyl-(1 → 3)-β-D-fucopyranosyl-(1 → 2)-β-D-galactopyranosyl-(1 → 4)-[β-D-quinovopyranosyl-(1 → 2)]-β-D-xylopyranosyl-(1 → 3)-β-D-quinovopyranosyl}-20-hydroxy-23-oxo-5α-cholest-9(11)-en-3β-yl sodium sulfate, was deduced principally from 1H 2D-COSY, J-resolved, nuclear Overhauser enhancement and selected decoupling experiments. The structure of forbeside B, 6α-O-{β-D-quinovopyranosyl-(1 → 2)-β-D-galactopyranosyl-(1 → 4)-[β-D-quinovopyranosyl-(1 → 2)]-β-D-xylopyranosyl-(1 → 3)-β-D-quinovopyranosyl}-20-hydroxy-23-oxo-5α-cholest-9(11)-en-3β-yl sodium sulfate, was deduced principally from 2D-COSY, HCORR, RECSY, and NOESY experiments.

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