ISSN:
0749-1581
Keywords:
13C NMR
;
Friedelanes
;
Triterpenoids
;
D/E ring conformation
;
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The 13C chemical shifts in the spectra of friedelan-7-one (1), methyl 3-oxofriedelan-25-oate (2), methyl friedelan-25-oate (3), 7-oxofriedelan-3-α-yl acetate (4), friedelan-3-one (5), 2-hydroxy-3, 4-seco-friedelan-3-oic acid (6), methyl 2-oxo-3,4-seco-friedelan-3-oate (7), methyl 2-hydroxy-3,4-seco-friedelan-3-oate (8) and 3,4-seco-friedelan-2,3-diol (9) have been fully assigned using two-dimensional heteronuclear correlation NMR spectroscopy, BB proton decoupled, DEPT and selective heteronuclear spin decoupling methods. These assignments and the observation of substantial NOEs between 26-methyl and 28-methyl and between 28-methyl and 30-methyl support the boat to boat conformations for the D and E rings in 1. Corrections and correlations are made of some earlier literature assignments of friedelanones.
Additional Material:
2 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrc.1260250110
Permalink
