105
norsesquiterpenoids (131 (normelanothyrsin A), 132, and 136), and bakkenolide A
(629) [44]. Characteristic features of these compounds are the substitution by an
angeloyloxy group at the C-1α position and the occurrence of a hydrogen atom at
C-10. The rearranged lactones, 557, 559, and 560, were each derived from a
12,8-lactone through hydrolysis and recyclization to C-6. The phytochemical profile of sample 2 was observed as being completely different from that of sample 1
[21]. Sample 2 produced fukinone (4), 198, 199, 200, 212, and 211, with all of these
bearing no substituent at C-1. However, the fact that all these compounds have a
hydrogen atom at C-10 was consistent with the constituents determined for sample
Fig. 31 7,8-Epoxyeremophilan-12,8-olides (1)
Chemical Constituents of Ligularia Species (Asteraceae) and Their Diversity…
norsesquiterpenoids (131 (normelanothyrsin A), 132, and 136), and bakkenolide A
(629) [44]. Characteristic features of these compounds are the substitution by an
angeloyloxy group at the C-1α position and the occurrence of a hydrogen atom at
C-10. The rearranged lactones, 557, 559, and 560, were each derived from a
12,8-lactone through hydrolysis and recyclization to C-6. The phytochemical profile of sample 2 was observed as being completely different from that of sample 1
[21]. Sample 2 produced fukinone (4), 198, 199, 200, 212, and 211, with all of these
bearing no substituent at C-1. However, the fact that all these compounds have a
hydrogen atom at C-10 was consistent with the constituents determined for sample
Fig. 31 7,8-Epoxyeremophilan-12,8-olides (1)
Chemical Constituents of Ligularia Species (Asteraceae) and Their Diversity…