An NMR study of the Lycopodium alkaloids, annotinine and annotine: verification of the annotine structure

Abstract

The Lycopodium alkaloids, annotinine and annotine, were examined by 1H and 13C NMR spectroscopy. Proton spectra were assigned by the application of double-quantum filtered phase-sensitive COSY and nuclear Overhauser enhancement difference spectra. These and other data confirmed the structure previously assigned to annotine. The 13C chemical shifts were consistent with the structural data derived from the proton spectra. The NMR data showed a good correlation with structures determined from molecular mechanics (MMX) calculations. Keywords: Lycopodium alkaloids 1H and 13C NMR, annotinine, annotine, structure of Lycopodium alkaloids, NMR alkaloids.