“…Further, in the 13 C-NMR spectra of 1 obtained by measurements using CDCl 3 , C 5 D 5 N, and CD 3 OD as solvents, the peak height of 11 signals, which were assigned to C-2-C-7, C-9, C-11, C-12, C-19, and C-20, was found to be fairly low and a signal due to C-1 could not be detected (Table 2). A similar phenomenon, which was ascribable to short spin-spin relaxation times, was reported in the case of the 13 C-NMR signals for sclareol (9 C-NMR spectra of 2 were similar to those of 1, except for the absence of signals due to one olefinic proton and one olefinic methine carbon, and the presence of a signal due to one olefinic quaternary carbon. In a manner similar to that in the case of 1, these 1 H-and 13 C-NMR signals were examined in detail, and the planar structure of 2 was determined, as shown in Fig.…”