11,12-Dihydroxy-10,6,8,11,13-icetexapentan-1-one

Abstract

The title compound [systematic name: 14,15-dihy­droxy-7,7-dimethyl-13-(propan-2-yl)tricyclo­[9.4.0.03,8]penta­deca-1(11),3(8),9,12,14-pentaen-4-one], C20H24O3, is a new icetexane diterpenoid which was isolated from the roots of Premna obtusifolia (Verbenaceae). The mol­ecule has three fused rings: a cyclo­hexenone, a central cyclo­heptene and a benzene ring. The cyclo­hexenone ring is in an envelope conformation, whereas the cyclo­heptene ring is in a twisted boat conformation. Intra­molecular O—H⋯O hydrogen bonds generate S(5) and S(8) ring motifs. In the crystal, mol­ecules are linked into dimers through O—H⋯O hydrogen bonds. These dimers are arranged in to sheets parallel to the ac plane. C—H⋯O and weak C—H⋯π inter­actions are also present.

Recent Developments with Icetexane Natural Products

“…As part of their study investigating novel radical scavengers and antioxidants, clinopodiolide D was evaluated in several assays including a thiobarbituric acid‐reactive substances screen (TBARS) with modest results. Fun and coworkers extracted the barbatusol type icetexane ( 63 , Figure 7) from the roots of Premna obtusifolia and elucidated its structure by X‐ray crystallographic techniques [44] …”

“…Fun and coworkers extracted the barbatusol type icetexane (63, Figure 7) from the roots of Premna obtusifolia and elucidated its structure by X-ray crystallographic techniques. [44] Salae and Boonnak reported the discovery of obtusinone D (64) and obtusinone E (65) from the root extracts of Premna obtusifolia. [45] Obtusinones D ( 64) and E ( 65) are constitutional hetero-dimeric isomers of each other joining two monomeric units of przewalskin E (55), fused by a putative hetero-Diels-Alder event in either a linear or angular manner, respectively (Figure 7.…”