Experimental

R factor = 0.053; wR factor = 0.131; data-to-parameter ratio = 8.2. The title compound [systematic name: (1,3,6,8,13,14,-16)-20-ethyl-8-ethoxy-3,13-dihydroxy-1,6,16-trimethoxy-4-(methoxymethyl)aconitan-14-yl 4-methoxybenzoate], C35H51NO10, was isolated from roots of Aconitum carmichaeli Debx., which is a typical C19-diterpenoid alkaloid. The molecule has an aconitane carbon skeleton with four six-membered rings and two five-membered rings. The six-membered rings adopt chair conformations or boat conforma-tions, while the five-membered rings have envelope confor-mations. Intramolecular O—H O and O—H N hydrogen bonds help to stabilize the molecular structure. Weak intermolecular C—H O interactions occur in the crystal structure