ent-(15S)-Pimar-8(14)-ene-15,16-diol

Abstract

The title compound {systematic name: (S)-1-[(2S,4aR,8aR)-2,4b,8,8-tetramethyl-2,3,4,4a,4b,5,6,7,8,8a,9,10-dodecahydrophenanthren-2-yl]ethane-1,2-diol}, C20H34O2, is an ent-pimarane diterpenoid which was isolated from the stem bark of Ceriops tagal. In the asymmetric unit, there are two crystallographically independent molecules, which are conformationally almost identical. In each molecule, the two cyclohexane rings of the fused three-ring system adopt chair conformations, while the cyclohexene ring is in an envelope conformation, with the methylene C atom next to the side chain as the flap atom. In the crystal, molecules are stacked in columns along the b axis through O—H...O hydrogen bonds.