4'-Bromo-butyl ent-16-oxobeyeran-19-oate.

The title compound, C(24)H(37)BrO(3), is a tetra-cyclic diterpenoid with a beyerane skeleton, synthesized by esterification of isosteviol. It comprises a fused four-ring system A/B/C/D. Rings A and B have a chair conformation, whereas ring C is an unsymmetrical distorted chair; the remaining five-membered ring D adopts an envelope conformation. The stereochemistry of the A/B and B/C ring junctions are trans, while the C/D junction is cis.