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13 C NMR spectroscopy of the withanolides and other highly oxygenated C 28 steroids
Author(s) -
Gottlied Hugo E.,
Kirson I.
Publication year - 1981
Publication title -
organic magnetic resonance
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0030-4921
DOI - 10.1002/mrc.1270160107
Subject(s) - conformational isomerism , side chain , chemistry , carbon skeleton , ring (chemistry) , molecule , withanolide , stereochemistry , nuclear magnetic resonance spectroscopy , substitution (logic) , carbon chain , crystallography , organic chemistry , medicine , alternative medicine , pathology , computer science , withania somnifera , programming language , polymer
The 13 C NMR spectra of 29 highly oxygenated C, steroids with the withanolide skeleton, 24 of which are naturally occurring substances or acetates thereof, were recorded and the carbon signals fully assigned. The shifts of the heavily functionalized A/B ring system can serve as a ‘fingerprint’ for the different substitution patterns. A study of the effects of hydroxyl substitution in the ring D/side chain part of the molecules leads to conformational information, including preferred rotamers around the 17—20 and 20—22 bonds. Systems with both 17α‐ and 17β‐oriented side chains are thus analysed.