5,6-Dihy­droxy-7,8-di­meth­oxy­flavone

Jing, L.-L.; Fan, X.-F.; Fan, P.-C.; He, L.; Jia, Z.-P.

doi:10.1107/S1600536813014451

organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 69| Part 7| July 2013| Page o1096

https://doi.org/10.1107/S1600536813014451

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5,6-Dihydroxy-7,8-dimethoxyflavone

Lin-Lin Jing,^a Xiao-Fei Fan,^a Peng-Cheng Fan,^a Lei He ^a and Zheng-Ping Jia ^a ^*

^aDepartment of Pharmacy, Lanzhou General Hospital of PLA, Key laboratory of the prevention and cure, for the plateau environment damage PLA, 730050, Lanzhou Gansu, People's Republic of China
^*Correspondence e-mail: zhengping_jia@yahoo.cn

(Received 12 April 2013; accepted 25 May 2013; online 15 June 2013)

The title compound (systematic name: 5,6-dihydroxy-7,8-dimethoxy-2-phenylchromen-4-one), C₁₇H₁₄O₆, is a flavone that was isolated from the petroleum ether-soluble fraction of the rare traditional Chinese medicinal herb Saussurea involucrata. The flavone molecule is almost planar, with a dihedral angle between the planes of the benzopyran-4-one group and the attached phenyl group of 1.89 (6)°. The 5-hydroxy group forms a strong intramolecular hydrogen bond with the carbonyl group, resulting in a six-membered hydrogen-bonded ring. The 6-hydroxy group also forms an intramolecular O—H⋯O contact. In the crystal, the molecules are linked by O—H⋯O and C—H⋯O hydrogen bonds and π–π interactions [3.37 (2)–3.39 (2) Å], which build up a three–dimensional network.

Related literature

For biological activity of Saussurea involucrata, see: Zheng et al. (1993 ); Gao et al. (2005 ); Tao et al.(2010 ); Ma et al. (2011 ); Jia et al. (2005 ); Liu et al. (1985 ). For related structures, see: Xiong et al. (2009 ); Vijayalakshmi et al. (1986 ); Paula et al. (2002 ).

Experimental

Crystal data

C₁₇H₁₄O₆
M_r = 314.28
Triclinic, $[P \overline 1]$
a = 7.953 (6) Å
b = 8.548 (6) Å
c = 10.951 (8) Å
α = 96.602 (8)°
β = 92.282 (8)°
γ = 100.279 (7)°
V = 726.3 (9) Å³
Z = 2
Mo Kα radiation
μ = 0.11 mm⁻¹
T = 295 K
0.21 × 0.16 × 0.09 mm

Data collection

Bruker APEXII CCD diffractometer
5252 measured reflections
3368 independent reflections
1786 reflections with I > 2σ(I)
R_int = 0.036

Refinement

R[F² > 2σ(F²)] = 0.070
wR(F²) = 0.236
S = 1.03
3368 reflections
212 parameters
H-atom parameters constrained
Δρ_max = 0.32 e Å⁻³
Δρ_min = −0.32 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O4—H4⋯O3ⁱ	0.82	2.05	2.764 (4)	146
C12—H12⋯O6ⁱⁱ	0.93	2.58	3.234 (4)	128
O3—H3⋯O2	0.82	1.84	2.564 (3)	146
O4—H4⋯O3	0.82	2.34	2.767 (3)	113
Symmetry codes: (i) -x, -y+1, -z; (ii) -x+2, -y+1, -z+1.

Data collection: APEX2 (Bruker, 2007 ); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 2012 ); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S1600536813014451/rk2401sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536813014451/rk2401Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S1600536813014451/rk2401Isup3.cml

checkCIF report

Comment top

Saussurea involucrata (Kar. et Kir) Sch.–Bip is one of the precious Tibetan herbs that have been used for a long period of time. Modern pharmacological studies have reported that the herb exhibit a wide range of bioactivitie, including antioxidation, anti–inflammatory, anti–fatigue, anti–hypoxia, anti–cancer and analgesic effects. (Zheng et al., 1993; Gao et al., 2005; Tao et al., 2010; Ma et al., 2011; Jia et al., 2005; Liu et al., 1985; Paula et al., 2002).

Our chemical investigation of this herbs for components with anti–hypoxia activity resulted in the isolation of the title compound and crystal growth one, suitable for X–ray diffraction.

The molecular structure of title compound is almost planar; the dihedral angle between the benzopyran–4–one group and the attached phenyl group is 1.89 (6)° (Fig. 1).

In the crystal,the 5–hydroxy group forms a strong intramolecular hydrogen bond with the carbonyl group, resulting in a six–membered ring (Fig. 1). The centrosymmetrical dimers of title compound is linked by intermolecular O4—H4···O3ⁱ hydrogen bonds. Non–classical C—H···O hydrogen bonds (C2—H2···O2ⁱⁱ, C15—H15···O2ⁱⁱ and C14—H14···O4ⁱⁱⁱ) and π–π interactions between molecule pairs (C3–C4–C5···C5ⁱ–C4ⁱ–C3ⁱ = 3.37 (2)–3.39 (2)Å are found in the crystal structure. All of these interactions build up a three–dimensional network. Symmetry codes: (i) -x, -y+1, -z; (ii) 1-x, -y, -z; (iii) 1+x, 1+y, z.

Related literature top

For biological activity of Saussurea involucrata, see: Zheng et al. (1993); Gao et al. (2005); Tao et al.(2010); Ma et al. (2011); Jia et al. (2005); Liu et al. (1985). For related structures, see: Xiong et al. (2009); Vijayalakshmi et al. (1986); Paula et al. (2002).

Experimental top

The air–dried whole plants (10 kg) of S. involucrate were milled and extracted with 70% ethanol (150 L×3) for 2 h each time at 351 K. The resulting extract was concentrated to give ethanol extract (2.4 kg). The ethanol extract was suspended in water and extracted successively with equal volumes petroleum ether, EtOAc and n–BuOH. The petroleum ether extract (1.2 kg) was subjected to a silica gel column eluted with petroleum ether–EtOAc (10:0 to 1:2, v/v) to afford five fractions. Fraction 5 was purified repeatedly over a Sephadex LH–20 column with a mixture of CHCl₃–MeOH (1:1, v/v) to give title compound (500 mg). Single crystals suitable for X–ray diffraction analysis were obtained by slow evaporation from MeOH at room temperature.

¹H–NMR (600 MHz, DMS–d6), δ (p.p.m.): 5.53 (1H, s, –OH), 12.27 (1H, s, –OH), 7.94 (2H, m), 7.57 (3H, m), 6.70 (1H, s), 4.16 (3H, s), 4.12 (3H, s). ¹³C–NMR (100 MHz, DMS–d6), δ (p.p.m.): 183.0, 164.2, 146.8, 143.1, 142.1, 133.3, 133.1, 132.0, 131.4, 129.1, 126.3, 106.8, 105.1, 62.2, 61.5.

Structure description top

Our chemical investigation of this herbs for components with anti–hypoxia activity resulted in the isolation of the title compound and crystal growth one, suitable for X–ray diffraction.

The molecular structure of title compound is almost planar; the dihedral angle between the benzopyran–4–one group and the attached phenyl group is 1.89 (6)° (Fig. 1).

For biological activity of Saussurea involucrata, see: Zheng et al. (1993); Gao et al. (2005); Tao et al.(2010); Ma et al. (2011); Jia et al. (2005); Liu et al. (1985). For related structures, see: Xiong et al. (2009); Vijayalakshmi et al. (1986); Paula et al. (2002).

Computing details top

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 2012); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures top

Fig. 1. Molecular structure of the title compound with the atom numbering scheme. Displacement ellipsoids are drawn at the 30% probability level. H atoms are presented as a small spheres of arbitrary radius. Hydrogen bond is shown as dashed lines.

5,6-dihydroxy-7,8-dimethoxy-2-phenylchromen-4-one top

Crystal data top

C₁₇H₁₄O₆	Z = 2
M_r = 314.28	F(000) = 328
Triclinic, P1	D_x = 1.437 Mg m⁻³
a = 7.953 (6) Å	Mo Kα radiation, λ = 0.71073 Å
b = 8.548 (6) Å	Cell parameters from 1607 reflections
c = 10.951 (8) Å	θ = 2.4–28.0°
α = 96.602 (8)°	µ = 0.11 mm⁻¹
β = 92.282 (8)°	T = 295 K
γ = 100.279 (7)°	Block, orange
V = 726.3 (9) Å³	0.21 × 0.16 × 0.09 mm

Data collection top

Bruker APEXII CCD diffractometer	1786 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	R_int = 0.036
Graphite monochromator	θ_max = 28.3°, θ_min = 2.4°
φ and ω scans	h = −9→10
5252 measured reflections	k = −10→11
3368 independent reflections	l = −14→14

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.070	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.236	H-atom parameters constrained
S = 1.03	w = 1/[σ²(F_o²) + (0.1286P)²] where P = (F_o² + 2F_c²)/3
3368 reflections	(Δ/σ)_max < 0.001
212 parameters	Δρ_max = 0.32 e Å⁻³
0 restraints	Δρ_min = −0.32 e Å⁻³

Crystal data top

C₁₇H₁₄O₆	γ = 100.279 (7)°
M_r = 314.28	V = 726.3 (9) Å³
Triclinic, P1	Z = 2
a = 7.953 (6) Å	Mo Kα radiation
b = 8.548 (6) Å	µ = 0.11 mm⁻¹
c = 10.951 (8) Å	T = 295 K
α = 96.602 (8)°	0.21 × 0.16 × 0.09 mm
β = 92.282 (8)°

Data collection top

Bruker APEXII CCD diffractometer	1786 reflections with I > 2σ(I)
5252 measured reflections	R_int = 0.036
3368 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.070	0 restraints
wR(F²) = 0.236	H-atom parameters constrained
S = 1.03	Δρ_max = 0.32 e Å⁻³
3368 reflections	Δρ_min = −0.32 e Å⁻³
212 parameters

Special details top

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R–factor wR and goodness of fit S are based on F², conventional R–factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R–factors(gt) etc. and is not relevant to the choice of reflections for refinement. R–factors based on F² are statistically about twice as large as those based on F, and R–factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
O1	0.6956 (2)	0.4357 (2)	0.24860 (16)	0.0386 (5)
O2	0.3542 (3)	0.1892 (2)	−0.02333 (18)	0.0489 (6)
O3	0.1717 (2)	0.4078 (2)	0.00746 (18)	0.0450 (5)
H3	0.1947	0.3212	−0.0196	0.067*
O4	0.1217 (3)	0.6852 (2)	0.14665 (19)	0.0512 (6)
H4	0.0594	0.6291	0.0909	0.077*
O5	0.3574 (3)	0.8349 (2)	0.32644 (18)	0.0528 (6)
O6	0.6457 (2)	0.7095 (2)	0.38048 (16)	0.0450 (5)
C1	0.7247 (3)	0.2981 (3)	0.1857 (2)	0.0354 (6)
C2	0.6135 (4)	0.2132 (3)	0.0965 (3)	0.0405 (7)
H2	0.6368	0.1175	0.0576	0.049*
C3	0.4604 (3)	0.2653 (3)	0.0593 (2)	0.0359 (6)
C4	0.4325 (3)	0.4143 (3)	0.1259 (2)	0.0303 (6)
C5	0.2887 (3)	0.4797 (3)	0.1000 (2)	0.0334 (6)
C6	0.2615 (3)	0.6188 (3)	0.1678 (2)	0.0367 (6)
C7	0.3817 (4)	0.6939 (3)	0.2618 (2)	0.0377 (7)
C8	0.5273 (3)	0.6333 (3)	0.2885 (2)	0.0360 (6)
C9	0.5500 (3)	0.4924 (3)	0.2197 (2)	0.0338 (6)
C10	0.8873 (3)	0.2593 (3)	0.2294 (2)	0.0362 (6)
C11	0.9879 (4)	0.3551 (4)	0.3266 (3)	0.0457 (7)
H11	0.9524	0.4461	0.3637	0.055*
C12	1.1388 (4)	0.3168 (4)	0.3683 (3)	0.0555 (9)
H12	1.2037	0.3809	0.4340	0.067*
C13	1.1942 (4)	0.1838 (4)	0.3130 (3)	0.0558 (9)
H13	1.2969	0.1584	0.3407	0.067*
C14	1.0974 (4)	0.0895 (4)	0.2172 (3)	0.0569 (9)
H14	1.1342	−0.0010	0.1805	0.068*
C15	0.9459 (4)	0.1264 (4)	0.1742 (3)	0.0492 (8)
H15	0.8826	0.0620	0.1079	0.059*
C16	0.2964 (6)	0.8185 (5)	0.4437 (4)	0.0927 (14)
H16A	0.1833	0.7547	0.4353	0.139*
H16B	0.2929	0.9224	0.4862	0.139*
H16C	0.3712	0.7671	0.4897	0.139*
C17	0.7790 (5)	0.8185 (4)	0.3370 (3)	0.0655 (10)
H17A	0.8386	0.7615	0.2774	0.098*
H17B	0.8575	0.8694	0.4048	0.098*
H17C	0.7313	0.8982	0.2995	0.098*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0383 (11)	0.0392 (11)	0.0415 (10)	0.0216 (9)	−0.0029 (8)	−0.0015 (8)
O2	0.0437 (12)	0.0463 (12)	0.0544 (12)	0.0171 (9)	−0.0080 (9)	−0.0127 (9)
O3	0.0383 (12)	0.0452 (12)	0.0511 (12)	0.0182 (9)	−0.0083 (9)	−0.0080 (9)
O4	0.0429 (13)	0.0525 (13)	0.0612 (14)	0.0296 (10)	−0.0074 (10)	−0.0096 (10)
O5	0.0668 (15)	0.0453 (12)	0.0497 (12)	0.0305 (11)	0.0005 (10)	−0.0101 (9)
O6	0.0451 (12)	0.0519 (12)	0.0370 (11)	0.0143 (10)	−0.0040 (9)	−0.0044 (9)
C1	0.0384 (16)	0.0329 (14)	0.0393 (15)	0.0161 (12)	0.0063 (12)	0.0063 (11)
C2	0.0404 (17)	0.0367 (15)	0.0476 (16)	0.0201 (13)	0.0026 (13)	−0.0020 (12)
C3	0.0344 (15)	0.0381 (15)	0.0365 (14)	0.0121 (12)	0.0019 (11)	0.0009 (11)
C4	0.0321 (14)	0.0321 (14)	0.0290 (13)	0.0118 (11)	0.0047 (10)	0.0031 (10)
C5	0.0310 (15)	0.0388 (15)	0.0315 (13)	0.0112 (12)	0.0005 (11)	0.0027 (10)
C6	0.0340 (15)	0.0395 (15)	0.0406 (15)	0.0186 (12)	0.0018 (11)	0.0035 (11)
C7	0.0423 (17)	0.0371 (15)	0.0376 (14)	0.0198 (13)	0.0069 (12)	−0.0001 (11)
C8	0.0402 (16)	0.0409 (15)	0.0277 (13)	0.0140 (12)	0.0011 (11)	−0.0017 (10)
C9	0.0320 (15)	0.0403 (15)	0.0329 (14)	0.0166 (12)	0.0016 (11)	0.0052 (11)
C10	0.0338 (15)	0.0364 (15)	0.0433 (15)	0.0141 (12)	0.0069 (12)	0.0121 (11)
C11	0.0458 (18)	0.0488 (18)	0.0464 (16)	0.0202 (14)	0.0006 (13)	0.0051 (13)
C12	0.046 (2)	0.068 (2)	0.0549 (19)	0.0154 (17)	−0.0082 (15)	0.0124 (16)
C13	0.0407 (19)	0.065 (2)	0.071 (2)	0.0237 (17)	0.0030 (16)	0.0252 (18)
C14	0.048 (2)	0.0475 (19)	0.082 (2)	0.0252 (16)	0.0080 (17)	0.0113 (17)
C15	0.0446 (18)	0.0439 (17)	0.0628 (19)	0.0200 (14)	0.0016 (14)	0.0043 (14)
C16	0.134 (4)	0.090 (3)	0.066 (2)	0.055 (3)	0.041 (2)	−0.006 (2)
C17	0.064 (2)	0.063 (2)	0.060 (2)	−0.0004 (18)	0.0005 (17)	−0.0104 (16)

Geometric parameters (Å, º) top

O1—C1	1.355 (3)	C7—C8	1.384 (4)
O1—C9	1.372 (3)	C8—C9	1.389 (4)
O2—C3	1.250 (3)	C10—C11	1.393 (4)
O3—H3	0.8200	C10—C15	1.388 (4)
O3—C5	1.360 (3)	C11—H11	0.9300
O4—H4	0.8200	C11—C12	1.374 (4)
O4—C6	1.359 (3)	C12—H12	0.9300
O5—C7	1.375 (3)	C12—C13	1.377 (5)
O5—C16	1.404 (4)	C13—H13	0.9300
O6—C8	1.372 (3)	C13—C14	1.365 (4)
O6—C17	1.417 (4)	C14—H14	0.9300
C1—C2	1.343 (4)	C14—C15	1.378 (4)
C1—C10	1.467 (4)	C15—H15	0.9300
C2—H2	0.9300	C16—H16A	0.9600
C2—C3	1.429 (4)	C16—H16B	0.9600
C3—C4	1.450 (4)	C16—H16C	0.9600
C4—C5	1.393 (4)	C17—H17A	0.9600
C4—C9	1.385 (4)	C17—H17B	0.9600
C5—C6	1.384 (4)	C17—H17C	0.9600
C6—C7	1.391 (4)

C1—O1—C9	119.6 (2)	C4—C9—C8	121.7 (2)
C5—O3—H3	109.5	C11—C10—C1	121.1 (2)
C6—O4—H4	109.5	C15—C10—C1	120.8 (3)
C7—O5—C16	114.1 (3)	C15—C10—C11	118.1 (3)
C8—O6—C17	112.7 (2)	C10—C11—H11	119.6
O1—C1—C10	111.1 (2)	C12—C11—C10	120.8 (3)
C2—C1—O1	121.9 (2)	C12—C11—H11	119.6
C2—C1—C10	127.0 (2)	C11—C12—H12	119.9
C1—C2—H2	119.0	C11—C12—C13	120.2 (3)
C1—C2—C3	122.1 (2)	C13—C12—H12	119.9
C3—C2—H2	119.0	C12—C13—H13	120.2
O2—C3—C2	123.7 (2)	C14—C13—C12	119.5 (3)
O2—C3—C4	120.9 (2)	C14—C13—H13	120.2
C2—C3—C4	115.4 (2)	C13—C14—H14	119.5
C5—C4—C3	121.9 (2)	C13—C14—C15	121.0 (3)
C9—C4—C3	119.3 (2)	C15—C14—H14	119.5
C9—C4—C5	118.8 (2)	C10—C15—H15	119.8
O3—C5—C4	120.6 (2)	C14—C15—C10	120.3 (3)
O3—C5—C6	118.5 (2)	C14—C15—H15	119.8
C6—C5—C4	120.9 (2)	O5—C16—H16A	109.5
O4—C6—C5	122.7 (2)	O5—C16—H16B	109.5
O4—C6—C7	118.5 (2)	O5—C16—H16C	109.5
C5—C6—C7	118.8 (2)	H16A—C16—H16B	109.5
O5—C7—C6	118.7 (2)	H16A—C16—H16C	109.5
O5—C7—C8	119.5 (2)	H16B—C16—H16C	109.5
C8—C7—C6	121.7 (2)	O6—C17—H17A	109.5
O6—C8—C7	121.1 (2)	O6—C17—H17B	109.5
O6—C8—C9	120.8 (2)	O6—C17—H17C	109.5
C7—C8—C9	118.1 (2)	H17A—C17—H17B	109.5
O1—C9—C4	121.7 (2)	H17A—C17—H17C	109.5
O1—C9—C8	116.6 (2)	H17B—C17—H17C	109.5

O1—C1—C2—C3	2.1 (4)	C3—C4—C9—C8	−178.3 (2)
O1—C1—C10—C11	2.1 (4)	C4—C5—C6—O4	−179.0 (2)
O1—C1—C10—C15	−177.4 (3)	C4—C5—C6—C7	0.8 (4)
O2—C3—C4—C5	−0.7 (4)	C5—C4—C9—O1	−179.0 (2)
O2—C3—C4—C9	177.8 (2)	C5—C4—C9—C8	0.3 (4)
O3—C5—C6—O4	0.9 (4)	C5—C6—C7—O5	177.9 (2)
O3—C5—C6—C7	−179.3 (2)	C5—C6—C7—C8	0.3 (4)
O4—C6—C7—O5	−2.3 (4)	C6—C7—C8—O6	179.2 (2)
O4—C6—C7—C8	−179.9 (3)	C6—C7—C8—C9	−1.0 (4)
O5—C7—C8—O6	1.6 (4)	C7—C8—C9—O1	−180.0 (2)
O5—C7—C8—C9	−178.6 (2)	C7—C8—C9—C4	0.7 (4)
O6—C8—C9—O1	−0.2 (4)	C9—O1—C1—C2	−1.1 (4)
O6—C8—C9—C4	−179.5 (2)	C9—O1—C1—C10	179.3 (2)
C1—O1—C9—C4	−1.3 (4)	C9—C4—C5—O3	179.1 (2)
C1—O1—C9—C8	179.4 (2)	C9—C4—C5—C6	−1.1 (4)
C1—C2—C3—O2	180.0 (3)	C10—C1—C2—C3	−178.3 (2)
C1—C2—C3—C4	−0.9 (4)	C10—C11—C12—C13	1.0 (5)
C1—C10—C11—C12	179.0 (3)	C11—C10—C15—C14	1.5 (5)
C1—C10—C15—C14	−178.9 (3)	C11—C12—C13—C14	−0.6 (5)
C2—C1—C10—C11	−177.5 (3)	C12—C13—C14—C15	0.7 (5)
C2—C1—C10—C15	3.0 (4)	C13—C14—C15—C10	−1.2 (5)
C2—C3—C4—C5	−179.9 (2)	C15—C10—C11—C12	−1.5 (5)
C2—C3—C4—C9	−1.3 (4)	C16—O5—C7—C6	103.2 (4)
C3—C4—C5—O3	−2.4 (4)	C16—O5—C7—C8	−79.2 (4)
C3—C4—C5—C6	177.5 (2)	C17—O6—C8—C7	−92.6 (3)
C3—C4—C9—O1	2.4 (4)	C17—O6—C8—C9	87.6 (3)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O4—H4···O3ⁱ	0.82	2.05	2.764 (4)	146
C12—H12···O6ⁱⁱ	0.93	2.58	3.234 (4)	128
O3—H3···O2	0.82	1.84	2.564 (3)	146
O4—H4···O3	0.82	2.34	2.767 (3)	113
C11—H11···O1	0.93	2.34	2.675 (4)	101

Symmetry codes: (i) −x, −y+1, −z; (ii) −x+2, −y+1, −z+1.

Experimental details

Crystal data
Chemical formula	C₁₇H₁₄O₆
M_r	314.28
Crystal system, space group	Triclinic, P1
Temperature (K)	295
a, b, c (Å)	7.953 (6), 8.548 (6), 10.951 (8)
α, β, γ (°)	96.602 (8), 92.282 (8), 100.279 (7)
V (Å³)	726.3 (9)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.11
Crystal size (mm)	0.21 × 0.16 × 0.09

Data collection
Diffractometer	Bruker APEXII CCD
Absorption correction	–
No. of measured, independent and observed [I > 2σ(I)] reflections	5252, 3368, 1786
R_int	0.036
(sin θ/λ)_max (Å⁻¹)	0.668

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.070, 0.236, 1.03
No. of reflections	3368
No. of parameters	212
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.32, −0.32

Computer programs: APEX2 (Bruker, 2007), SAINT (Bruker, 2007), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 2012), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O4—H4···O3ⁱ	0.82	2.05	2.764 (4)	146
C12—H12···O6ⁱⁱ	0.93	2.58	3.234 (4)	128
O3—H3···O2	0.82	1.84	2.564 (3)	146
O4—H4···O3	0.82	2.34	2.767 (3)	113
C11—H11···O1	0.93	2.34	2.675 (4)	101

Symmetry codes: (i) −x, −y+1, −z; (ii) −x+2, −y+1, −z+1.

Acknowledgements

We thank the Natural Science Foundation of China (grant No. 81202458) and China Postdoctoral Science Foundation (grant No. 2012M521926) for financial support.

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