Three New Atisane Diterpenoids fromSpiraea japonica

Three new atisane diterpenoids, spiratisanins A – C (1 – 3, resp.), featuring a phenylacryloxyl substituted ent-atisane skeleton, were isolated from Spiraea japonica together with two known atisine diterpene alkaloids, spiramine A (4) and spiradine F (5). The structures of these new compounds were elucidated as (5β,7α,8α,9β,10α,12α,16β)-16-hydroxyatisan-7-yl (2E)-3-phenylprop-2-enoate (1), (5β,7α,8α,9β,10α,12α,16α)-16-hydroxyatisan-7-yl (2E)-3-phenylprop-2-enoate (2), and (5β,8α,9β,10α,12α,16β)-16-hydroxyatisan-20-yl (2E)-3-phenylprop-2-enoate (3) on the basis of spectroscopic analysis.