C‐13 magnetic resonance studies of some papaveraceae alkaloids

Abstract The natural abundance 13 C magnetic resonance spectra of some Papaveraceae alkaloids have been determined at 22·628 MHz employing the pulse Fourier transform technique. Several techniques were employed to aid in spectral assignments and it has been possible to make self‐consistent assignments for all the resonances for these alkaloids. Evidence is presented for trans‐annular interaction between the amino group and the carbonyl group situated across the ten‐membered ring.