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Effects of N-oxidation on the 15N chemical shifts in the Strychnos alkaloids strychnine and brucine

✍ Scribed by Chad E. Hadden; Brian D. Kaluzny; Russell H. Robins; Gary E. Martin

Publisher
John Wiley and Sons
Year
1999
Tongue
English
Weight
77 KB
Volume
37
Category
Article
ISSN
0749-1581

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✦ Synopsis

The e †ects of N-oxidation on the 15N chemical shifts of the Strychnos alkaloids strychnine and brucine are discussed. The 15N shifts were determined using the inverse-detected, long-range GHMBC experiment at natural abundance. Following N-oxidation, the N-19 resonance shifted downÐeld from 35.0 ppm in strychnine to 136.3 ppm in the N-19-oxide. The N-19 resonance of brucine shifted downÐeld from 35.9 to 135.5 ppm in the N-19oxide. Small upÐeld shifts were observed for the N-9 resonances of both N-oxides. The 1H and 13C shifts of both N-oxides were assigned using inverse-detected 2D NMR methods to ensure proper assignments of the long-range 1HÈ15N couplings.

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