An NMR study of spatial arrangements in natural alkaloids—I: Indor spectra and conformations of pachycarpine (<i>d</i>‐sparteine), lupanine and 13‐hydroxylupanine

Abstract

Abstract The INDOR homonuclear PMR spectra of three quinolizidine alkaloids—pachycarpine ( d ‐sparteine), lupanine and 13‐hydroxylupanine—have been studied. The molecular conformations including the boat‐structure of the ring C have been established.