1,3,6-Trihydroxy-7-methoxy-2,8-bis(3- methylbut-2-enyl)-9H-xanthen-9-one Gwendoline Cheng Lian Ee,* Wei Chung Sim, Huey Chong Kwong, Mohamed Ibrahim Mohamed Tahir and Sidik Silong Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia Correspondence e-mail: gwen@science.upm.edu.my Received 23 November 2010; accepted 24 November 2010 Key indicators: single-crystal X-ray study; T = 150 K; mean (C–C) = 0.002 A ˚ ; R factor = 0.041; wR factor = 0.113; data-to-parameter ratio = 14.8. The title compound (trivial name -mangostin), C 24 H 26 O 6 , isolated from Cratoxylum glaucum, is characterized by a xanthone skeleton of three fused six-membered rings and two 3-methylbut-2-enyl side chains. The three rings in the structure are nearly coplanar, with an r.m.s. deviation for the tricyclic ring system of 0.0014 A ˚ . The two 3-methylbut-2-enyl side chains are in (+)-synclinal and (-)-anticlinal conformations. Intramolecular O—HO and C—HO interactions occur. The crystal structure is stabilized by intermolecular O— HO, C—HO and C—H interactions. Related literature For standard bond lengths, see Allen et al. (1987). For related structures, see: Marek et al. (2003); Ndjakou et al. (2007); Boonnak et al. (2007). For the biological activity of Cratox- ylum species, see: Boonnak et al. (2006); Bennett et al. (1993); Nguyen & Harrison (1998); Boonsri et al. (2006); Reutrakul et al. (2006). Experimental Crystal data C 24 H 26 O 6 M r = 410.47 Orthorhombic, Pbcn a = 14.6818 (3) A ˚ b = 9.53505 (19) A ˚ c = 29.8893 (6) A ˚ V = 4184.24 (14) A ˚ 3 Z =8 Cu K radiation  = 0.77 mm 1 T = 150 K 0.11  0.10  0.04 mm Data collection Oxford Diffraction Gemini E diffractometer Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2006) T min = 0.926, T max = 0.970 13773 measured reflections 4032 independent reflections 2812 reflections with I >2(I) R int = 0.034 Refinement R[F 2 >2(F 2 )] = 0.041 wR(F 2 ) = 0.113 S = 0.88 4018 reflections 271 parameters H-atom parameters constrained Á max = 0.34 e A ˚ 3 Á min = 0.27 e A ˚ 3 Table 1 Hydrogen-bond geometry (A ˚ ,  ). CgA is the mid-point of the C14 C15 double bond. D—HA D—H HA DA D—HA C13—H132O5 0.94 2.24 2.885 (3) 125 C14—H141O10 i 0.96 2.36 3.304 (3) 168 O21—H211O5 0.85 1.71 2.499 (3) 155 O10—H101O21 ii 0.84 1.88 2.691 (3) 164 O30—H301CgA 0.86 2.38 3.227 (3) 166 Symmetry codes: (i) x þ 3 2 ; y  1 2 ; z; (ii) x þ 1 2 ; y þ 1 2 ; z þ 1 2 . Data collection: CrysAlis CCD (Oxford Diffraction, 2006); cell refinement: CrysAlis CCD; data reduction: CrysAlis RED (Oxford Diffraction, 2006); program(s) used to solve structure: SIR92 (Alto- mare et al. , 1994); program(s) used to refine structure: CRYSTALS (Betteridge et al. , 2003); molecular graphics: Mercury (Macrae et al. , 2006); software used to prepare material for publication: CRYS- TALS. The author would like to acknowledge the Ministry of Science, Technology and Innovation (MOSTI) for e-science funding. Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: KP2293). References Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Prpen, A.G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–19. Altomare, A., Cascarano, G., Giacovazzo, C., Guagliardi, A., Burla, M. C., Polidori, G. & Camalli, M. (1994). J. Appl. Cryst. 27, 435. Bennett, G. J., Harrison, L. J., Sia, G. L. & Sim, K. Y. (1993). Phytochemistry, 32, 1245–1251. Betteridge, P. W., Carruthers, J. R., Cooper, R. I., Prout, K. & Watkin, D. J. (2003). J. Appl. Cryst. 36, 1487. Boonnak, N., Fun, H.-K., Chantrapromma, S. & Karalai, C. (2007). Acta Cryst. E63, o3958–o3959. Boonnak, N., Karalai, C., Chantrapromma, S., Ponglimanont, C., Fun, H.-K., Kanjana-Opas, A. & Laphookhieo, S. (2006). Tetrahedron, 62, 8850–8859. Boonsri, S., Karalai, C., Ponglimanont, C., Kanjana-opas, A. & Chantra- promma, K. (2006). Phytochemistry, 67, 723–727. Macrae, C. F., Edgington, P. R., McCabe, P., Pidcock, E., Shields, G. P., Taylor, R., Towler, M. & van de Streek, J. (2006). J. Appl. Cryst. 39, 453–457. Marek, J., Vesela ´, D., Lis ˇkova ´, M. & Z ˇ emlic ˇka, M. (2003). Acta Cryst. C59, o127–o128. Ndjakou Lenta, B., Devkota, K. P., Neumann, B., Tsamo, E. & Sewald, N. (2007). Acta Cryst. E63, o1629–o1631. organic compounds o3362 Ee et al. doi:10.1107/S1600536810049123 Acta Cryst. (2010). E66, o3362–o3363 Acta Crystallographica Section E Structure Reports Online ISSN 1600-5368