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Effects of N ‐oxidation on the 15 N chemical shifts in the Strychnos alkaloids strychnine and brucine
Author(s) -
Hadden Chad E.,
Kaluzny Brian D.,
Robins Russell H.,
Martin Gary E.
Publication year - 1999
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/(sici)1097-458x(199904)37:4<325::aid-mrc453>3.0.co;2-e
Subject(s) - brucine , chemistry , strychnine , chemical shift , stereochemistry , computational chemistry , organic chemistry , biochemistry
The effects of N ‐oxidation on the 15 Nchemical shifts of the Strychnos alkaloids strychnine andbrucine are discussed. The 15 N shifts were determinedusing the inverse‐detected, long‐range GHMBC experimentat natural abundance. Following N ‐oxidation, theN‐19 resonance shifted downfield from 35.0 ppm in strychnineto 136.3 ppm in the N ‐19‐oxide. The N‐19resonance of brucine shifted downfield from 35.9 to 135.5 ppm in the N ‐19‐oxide. Small upfield shifts were observedfor the N‐9 resonances of both N ‐oxides. The 1 H and 13 C shifts of both N ‐oxideswere assigned using inverse‐detected 2D NMR methods to ensureproper assignments of the long‐range 1 H– 15 N couplings. Copyright © 1999 John Wiley & Sons,Ltd.