(13E)-19-Hydroxylabda-8(17),13-dien-15-oic acid methyl ester

(E)-5-[(1S,4aα)-Decahydro-5β-(hydroxymethyl)-5α,8aβ-dimethyl-2-methylenenaphthalen-1β-yl]-3-methyl-2-pentenoic acid methyl ester