14-Acetyl-20-ethyl-1,8-dihydroxy-16,18-dimethoxylycoctonine

The title compound (C25H39NO6), a polycyclic diterpenoid alkaloid, has been isolated from Delphinium roylei Munz. Two cis-fused ring junctions are observed between cyclohexane A and piperidine E rings and between cyclohexane B and cyclopentane C rings. Two trans-fused ring junctions involve cyclohexane A and cyclopentane B rings and also piperidine E and cyclopentane F rings. Cyclopentane ring F is in a twist conformation, while the other cyclopentane ring, C, forms an envelope conformation. Piperidine ring E is in a chair conformation, the two cyclohexane rings A and B adopt twist-boat conformations and cyclohexane ring D is in a screw-boat conformation. Of the five substituents, only one is alpha-oriented. The molecules are packed along the c axis in layers parallel to the ab plane and stabilized by weak inter- and intramolecular O-H center dot center dot center dot O and O-H center dot center dot center dot N hydrogen bonds.