13C-NMR spectra of strychnos alkaloids: brucine and strychnine

The natural abundance 13C-NMR spectra of brucine and strychnine were obtained using the pulse Fourier transform technique. The chemical shifts of various carbon resonances were assigned on the basis of substituent effects on benzene shifts, intesities of signals, multiplicites generated in single-frequency off-resonance-decoupled spectra, and comparisons with the chemical shifts of structurally related compounds.