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Carbon‐13 n.m.r. analysis of selected strychnos alkaloids
Author(s) -
Leung J.,
Jones Alan J.
Publication year - 1977
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.1270090610
Subject(s) - strychnine , strychnos , chemistry , stereochemistry , chemical shift , computational chemistry , additive function , alkaloid , mathematical analysis , biochemistry , mathematics
Abstract The carbon‐13 chemical shifts of strychnine and ten closely related analogues have been assigned and confirmed in several cases using selective proton decoupling techniques. Where additivity relationships are used the importance of having data on an array of structural analogues is emphasized. Quaternization at N‐19 exerts long range polarization effects throughout the molecular framework. The effects of N ‐oxide formation on the carbon‐13 shifts of 5 to 9‐membered ring heterocycles and strychnine are discussed as aids to structural assignment. A Zwitterionic structure for strychnic acid is deduced.