title: 7-Acetoxy-cochinchinone I.
abstract: The title compound {systematic name: 12-[(2E)-3,7-dimethyl-2,6-octa-dien-yl]-5,8-dihydr-oxy-2,2-dimethyl-2H,6H-pyrano[3,2-b]xanthen-6-one}, C(30)H(32)O(6), has four fused rings (A/B/C/D) and the xanthone ring system (A/B/C) is essentially planar, with dihedral angles of 1.85 (13) and 2.47 (13)°, respectively, between rings A and B, and between rings B and C. The chromene ring D is in a sofa form. The geranyl side chain is axially attached to ring C with an (-)-synclinal conformation. The 3-methyl-2-butenyl terminal of the geranyl side chain is disordered with the site-occupancy ratio of 0.513 (5):0.487 (5). The acet-oxy group is attached axially to ring A with an (+)-synclinal conformation. An intra-molecular O-H⋯O hydrogen bond involving the carbonyl and hydroxyl groups generates an S(6) ring motif. In the crystal, weak C-H⋯O and C-H⋯π inter-actions, and π-π inter-actions with centroid-centroid distances of 3.6562 (16) and 3.6565 (16) Å are observed.
authors.forename: Suchada
authors.initials: S
authors.lastname: Chantrapromma
authors.forename: Nawong
authors.initials: N
authors.lastname: Boonnak
authors.forename: Hoong-Kun
authors.initials: HK
authors.lastname: Fun