“…[13] In addition, the spectroscopic data of one tertiary methyl group (δ(C) 29.8), six methylene groups (δ(C) 31.0, 31.7, 31.9, 36.8, 62.9, 109.5), eight methine groups (δ(C) 49.9, 53.8, 60.1, 63.3, 69.9, 70.0, 75.2, 81.4) and five quaternary carbons (δ(C) 37.6, 45.1, 46.3, 79.0, 143.7) further inferred that compound 1 was a hetisine-type C 20 -diterpenoid alkaloid. [8] By comparing the 13 C-NMR and MS features of 1 with those of known alkaloid Guan Fu base O (9), [14] their structures were very similar except for the propionyloxy group in 9 was substituted by the 2-methylbutanoyloxy group in 1.…”