1-Hydroxy-2-methoxy-6-methyl-9,10- anthraquinone from Rennellia elliptica Korth. Nor Hadiani Ismail, a Che Puteh Osman, a Rohaya Ahmad, a Khalijah Awang b and Seik Weng Ng b * a Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor Darul Ehsan, Malaysia, and b Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia Correspondence e-mail: seikweng@um.edu.my Received 8 May 2009; accepted 11 May 2009 Key indicators: single-crystal X-ray study; T = 100 K; mean (C–C) = 0.007 A ˚ ; R factor = 0.082; wR factor = 0.267; data-to-parameter ratio = 11.3. The title compound, C 16 H 12 O 4 , exists as planar molecules in the solid state (r.m.s. deviation of 0.02 A ˚ in one molecule and 0.07 A ˚ in the second independent molecule comprising the asymmetric unit). In each molecule, the 1-hydroxy group forms an intramolecular hydrogen bond to the adjacent carbonyl O atom. Related literature The existence of the title natural product has only been reported for Crucianella maritima L. (El-Lakany et al. , 2004). For another anthraquinone isolated from Rennellia elliptica Korth., see: Ismail et al. (2009). Experimental Crystal data C 16 H 12 O 4 M r = 268.26 Triclinic, P 1 a = 7.1755 (3) A ˚ b = 11.9082 (5) A ˚ c = 14.9683 (7) A ˚  = 91.409 (3)   = 100.603 (3)   = 105.666 (3)  V = 1206.73 (9) A ˚ 3 Z =4 Mo K radiation  = 0.11 mm 1 T = 100 K 0.25  0.20  0.01 mm Data collection Bruker SMART APEX diffractometer Absorption correction: none 6750 measured reflections 4142 independent reflections 2248 reflections with I >2(I) R int = 0.051 Refinement R[F 2 >2(F 2 )] = 0.082 wR(F 2 ) = 0.267 S = 1.08 4142 reflections 367 parameters H-atom parameters constrained Á max = 0.59 e A ˚ 3 Á min = 0.35 e A ˚ 3 Table 1 Hydrogen-bond geometry (A ˚ ,  ). D—HA D—H HA DA D—HA O3—H3O2 0.84 1.80 2.538 (4) 147 O7—H7O6 0.84 1.81 2.551 (5) 146 Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X- SEED (Barbour, 2001); software used to prepare material for publication: publCIF (Westrip, 2009). We thank Universiti Teknologi MARA and the University of Malaya for supporting this study. Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: TK2448). References Barbour, L. J. (2001). J. Supramol. Chem. 1, 189–191. Bruker (2008). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. El-Lakany, A. M., Aboul-Ela, M. A., Abdel-Kader, M. S., Badr, J. M., Sabri, N. N. & Goher, Y. (2004). Nat. Prod. Sci. 10, 63–68. Ismail, N. H., Osman, C. P., Ahmad, R., Awang, K. & Ng, S. W. (2009). Acta Cryst. E65, o1433–o1434. Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Westrip, S. P. (2009). publCIF. In preparation. organic compounds Acta Cryst. (2009). E65, o1435 doi:10.1107/S1600536809017619 Ismail et al. o1435 Acta Crystallographica Section E Structure Reports Online ISSN 1600-5368