C-13 NMR-SPECTROSCOPY OF NATURAL SUBSTANCES .4. C-13 NMR-STUDIES OF TRACHYLOBANE DITERPENES - COMPLETE CARBON ASSIGNMENT

The diterpene trachylobane and a series of derivatives have been completely analysed by FT 13C NMR spectroscopy. All 13C frequencies for trachylobanol have been unambiguously assigned by experimental techniques, i.e. by proton single‐frequency selective decoupling and shift reagent experiments. Shift calculations have been performed for the parent compound by using known methods. The results are discussed in comparison with the experimental data. Satisfactory agreement between predicted and experimental values has been obtained. Copyright © 1979 Heyden & Son Ltd.