Crystal structure of 1,5-dioxaspiro[5.5]undecane-2,4-dione, C9H12O4

C9H12O4, triclinic, P1 (no. 2), a = 9.459(2) Å, b = 9.473(2) Å, c = 20.390(4) Å, * = 88.15(3)°, ) = 88.60(3)°, & = 89.88(3)°, V = 1825.5 Å, Z = 8, Rgt(F) = 0.037, wRref(F) = 0.113, T = 293 K. Source of material All the reagents and solvents from commercial sources were used without further purification. The mixture of malonic acid (0.06 mol) and acetic anhydride (9 ml) in strong sulphuric acid (0.25 ml) was stirred at room tempertaure. After dissolving, cyclohexanone (0.06 mol) was added dropwise into solution for 1 h. After then, the reaction proceeded for 4 h. The solution was then filtered and concentrated, and the title compound was crystallized from ethanol (yield 75 %, m.p. 465 466 K). 10 mg of the crude product was dissolved in 15 mL ethanol, the solution was allowed to evaporate at room temperature, and light yellow single crystals were formed after 7 d. Discussion Spiro compounds have attracted the attention of scholars and scientists owing to their potential applications in medicine [1], catalysis and as optical materials [2]. Recently, the design and synthesis of spiro compounds containing oxygen have emerged an increasing interest due to their biological activities such as antiandrogenic, antitumor and antiviral activity. Many spiro compounds possessing high biological activities and special structures have been synthesized over the past decades [3,4]. In the asymmetric unit of the title crystal structure, there are four crystallographically independent molecules . Each molecule consists of 1,3-dioxane ring and cyclohexane ring, and they do not share a common plane. The six-membered rings of the four independent molecules, (O1/C4/O2/C9/C8/C7), (O5/C13/O6/C18/ C17/C16), (O9/C22/O10/C25-C27), (O13/C31/O14/C36/C35/ C34), (C1-C6), (C10-C15), (C19-C24), (C28-C33) have chair comformations with the puckering parameters Q = 0.446 Å, + = 105.3°, # = 235.7°; Q = 0.456 Å, + = 106.5°, # = 236.86°; Q = 0.453 Å, + = 107.0°, # = 242.95°; Q = 0.445 Å, + = 73.9°, # = 56.6°; Q = 0.549 Å, + = 2.6°, # = 347.11°; Q = 0.549 Å, + = 178.3°, # = 176.84°; Q = 0.552 Å, + = 2.1°, # = 355.58°; and Q = 0.546 Å, + = 2.9°, # = 0.90°, respectively [5]. The C—O bond lengths in the range of (1.4393(1) 1.4476(2) Å) are in good ageement with the values reported earier [6]. In the crystal structure, weak intraand intermolecular C–H···O hydrogen bonds link the molecules into chains extended along [100], and the title molecule forms hydrogen bonded dimers. 498 Z. Kristallogr. NCS 225 (2010) 498-500 / DOI 10.1524/ncrs.2010.0218 © by Oldenbourg Wissenschaftsverlag, München Crystal: colorless block, size 0.18 × 0.21 × 0.35 mm Wavelength: Mo K* radiation (0.71073 Å) -: 1.06 cm−1 Diffractometer, scan mode: Bruker SMART CCD, #/% 2+max: 54.96° N(hkl)measured, N(hkl)unique: 18145, 8316 Criterion for Iobs, N(hkl)gt: Iobs > 2 ((Iobs), 5806 N(param)refined: 470 Programs: SHELXS-97, SHELXL-97, SHELXTL [7], PLATON [8] Table 1. Data collection and handling. H(35A) 2i 0.4654 0.8272 0.0128 0.054 H(35B) 2i 0.3463 0.9277 0.0383 0.054 H(30A) 2i 0.3822 0.6178 0.2353 0.061 H(30B) 2i 0.5464 0.5959 0.2376 0.061 H(32A) 2i 0.6847 0.5961 0.1218 0.055 H(32B) 2i 0.5919 0.6173 0.0596 0.055 H(33A) 2i 0.4869 0.3988 0.0779 0.069 H(33B) 2i 0.6514 0.3768 0.0780 0.069 H(29A) 2i 0.4407 0.3775 0.2541 0.072 H(29B) 2i 0.3524 0.3990 0.1904 0.072 H(28A) 2i 0.5408 0.2500 0.1667 0.077 H(28B) 2i 0.6490 0.3600 0.1920 0.077 H(26A) 2i 0.6671 0.5361 0.4871 0.053 H(26B) 2i 0.5668 0.6565 0.4621 0.053 H(23A) 2i 0.8924 0.3181 0.3782 0.054 H(23B) 2i 0.8704 0.4100 0.4404 0.054 H(24A) 2i 1.0898 0.5163 0.4226 0.067 H(24B) 2i 1.1125 0.3521 0.4234 0.067 Table 2. Atomic coordinates and displacement parameters (in Å). Atom Site x y z Uiso