title: Caloxanthone C: a pyran-oxanthone from the stem bark of Calophyllum soulattri.
abstract: THE TITLE COMPOUND [SYSTEMATIC NAME: 5,10-di-hy-droxy-2,2-di-methyl-12-(2-methyl-but-3-en-2-yl)-pyrano[3,2-b]xanthen-6(2H)-one], C(23)H(22)O(5), isolated from the stem bark of Calophyllum soulattri, consists of four six-membered rings and a 2-methyl-but-3-en-2-yl side chain. The tricyclic xanthone ring system is almost planar [maximum deviation = 0.093 (2) Å], whereas the pyran-oid ring is in a distorted boat conformation. The 2-methyl-but-3-en-2-yl side chain is in a synperiplanar conformation. There are two intra-molecular O-H⋯O hydrogen bonds. In the crystal, mol-ecules are linked by C-H⋯O inter-actions, forming a zigzag chain propagating in [010].
authors: Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor,  Malaysia.
authors: Gwendoline Cheng Lian
authors: GC
authors: Ee
authors: Siau Hui
authors: SH
authors: Mah
authors: Huey Chong
authors: HC
authors: Kwong
authors: Soek Sin
authors: SS
authors: Teh
authors: Mohamed Ibrahim
authors: MI
authors: Mohamed Tahir
authors: Sidik
authors: S
authors: Silong