2-(2-{2-[2-(Dibromo­meth­yl)phen­oxy]eth­oxy}benz­yloxy)benzaldehyde

Xia, J.; Liu, X.; Wang, A.-Q.; Su, Z.-X.

doi:10.1107/S160053681100643X

organic compounds

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ISSN: 2056-9890

Volume 67| Part 3| March 2011| Page o714

doi:10.1107/S160053681100643X

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2-(2-{2-[2-(Dibromomethyl)phenoxy]ethoxy}benzyloxy)benzaldehyde

Juan Xia,^a Xiang Liu,^a An-Qi Wang ^a and Zhong-Xing Su ^a ^*

^aState Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, People's Republic of China
^*Correspondence e-mail: zxsu@lzu.edu.cn

(Received 21 December 2010; accepted 20 February 2011; online 26 February 2011)

The molecule of the title compound, C₂₃H₂₀Br₂O₄, adopts a Z conformation as a result of intermolecular C—H⋯Br bonding. One benzene ring, with the structure R-CHBr₂, makes a dihedral angle of 63.0 (2)° with the other benzene ring attached to the aldehyde group. Intermolecular π–π stacking interactions [centroid–centroid distance = 3.698 (4) Å] and a weak C—H⋯Br contact is present in the crystal structure.

Related literature

For general background to the biological activity of salicylaldehydes and their derivatives, see: Jahnke et al. (1993 ); Pelttari et al. (2007 ); Fillebeen & Pantopoulos (2010 ); Fan et al. (2010 ). For related structures, see: Mori et al. (2010 ); Potapov et al. (2009 ); Purushothaman & Raghunathan (2009 ). For the preparation of the title compound, see: Purushothaman & Raghunathan (2009); Zhang et al. (2010 ).

Experimental

Crystal data

C₂₃H₂₀Br₂O₄
M_r = 520.19
Monoclinic, P 2₁ /c
a = 12.867 (7) Å
b = 18.07 (1) Å
c = 9.649 (5) Å
β = 108.955 (6)°
V = 2122 (2) Å³
Z = 4
Mo Kα radiation
μ = 3.85 mm⁻¹
T = 296 K
0.34 × 0.32 × 0.28 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ) T_min = 0.281, T_max = 0.341
15392 measured reflections
3944 independent reflections
1905 reflections with I > 2σ(I)
R_int = 0.063

Refinement

R[F² > 2σ(F²)] = 0.062
wR(F²) = 0.207
S = 1.02
3944 reflections
263 parameters
H-atom parameters constrained
Δρ_max = 0.79 e Å⁻³
Δρ_min = −0.75 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C5—H5⋯Br1ⁱ	0.93	3.03	3.529 (7)	116
Symmetry code: (i) $[-x+1, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]$ .

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: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S160053681100643X/rk2257sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S160053681100643X/rk2257Isup2.hkl

checkCIF report

Comment top

It is reported that salicylaldehydes and their derivatives have showed a wide variety of biological activities, such as antiseptic, labelling cell, antiproliferative and pesticidal (Jahnke et al., 1993; Pelttari et al., 2007; Fillebeen & Pantopoulos, 2010; Fan et al., 2010). As an important class of aldehydes, substituted aldehydes also exhibit potential biological activities. The related structures also have been reported (Mori et al., 2010; Potapov et al., 2009; Purushothaman & Raghunathan, 2009). On this base, the title compound was synthesized.

In the title compound (Fig. 1), a dihedral angle 63.0 (2)° is observed between benzene rings on the both ends of molecule. The crystal structure is stabilized by weak intramolecular C—H···O bonds.

The molecule of the title compound is linked by the C—H···Br bonding (Fig. 2) in to the Z formation.

Furthermore, the weak intermolecular π–π stacking interactions - Cg1···Cg2ⁱⁱ= 3.698 (4)Å, Cg3···Cg3ⁱⁱⁱ = 4.193 (5)Å, where Cg1 is centroid of the ring C2–C7, Cg2 is centroid of the ring C9–C14 and Cg3 is centroid of the ring C17–C22. Symmetry codes: (ii) -x, 1-y, -z; (iii) 1-x, 1-y, 1-z.

Related literature top

For general background to the biological activity of salicylaldehydes and their derivatives, see: Jahnke et al. (1993); Pelttari et al. (2007); Fillebeen & Pantopoulos (2010); Fan et al. (2010). For related structures, see: Mori et al. (2010); Potapov et al. (2009); Purushothaman & Raghunathan (2009). For the preparation of the title compound, see: Purushothaman & Raghunathan (2009); Zhang et al. (2010).

Experimental top

All reagents and solvents were obtained from commercial sources and needed to be further purified. The title compound was synthesized according to the related literature (Purushothaman & Raghunathan, 2009). A solution of salicylaldehyde (2 mmol in 10 ml acetone) was slowly added dropwise to a suspension of 1,2-bis(2-(bromomethyl)phenoxy) ethane (1 mmol in 20 ml acetone) prepared according to the reported method (Zhang et al., 2010) and anhydrous potassium carbonate (2 mmol). The mixture was refluxed for 8 h. The reaction mixture was then cooled to room temperature and filtered. After this period, the residue was dissolved and extracted by ethyl acetate. The combined organical layer was washed with water and then dried with anhydrous sodium sulfate. After that the solvent was evaporated under vacuum to give the product. The obtained residue was purified by flash column chromatography on silica gel using petroleum ether/ethylacetate (5:2) mixtures as eluent.

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: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

	Fig. 1. The 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.
	Fig. 2. A view of the C—H···Brⁱ interactions in the crystal structure of the title compound. Symmetry code: (i) -x+1, y+1/2, -z+1/2).

2-(2-{2-[2-(Dibromomethyl)phenoxy]ethoxy}benzyloxy)benzaldehyde top

Crystal data top

C₂₃H₂₀Br₂O₄	F(000) = 1040
M_r = 520.19	D_x = 1.628 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 1808 reflections
a = 12.867 (7) Å	θ = 2.3–17.5°
b = 18.07 (1) Å	µ = 3.85 mm⁻¹
c = 9.649 (5) Å	T = 296 K
β = 108.955 (6)°	Block, colourless
V = 2122 (2) Å³	0.34 × 0.32 × 0.28 mm
Z = 4

Data collection top

Bruker APEXII CCD diffractometer	3944 independent reflections
Radiation source: fine-focus sealed tube	1905 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.063
ϕ and ω scans	θ_max = 25.5°, θ_min = 2.3°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −15→15
T_min = 0.281, T_max = 0.341	k = −21→21
15392 measured reflections	l = −11→11

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.062	H-atom parameters constrained
wR(F²) = 0.207	w = 1/[σ²(F_o²) + (0.1049P)² + 0.4797P] where P = (F_o² + 2F_c²)/3
S = 1.02	(Δ/σ)_max < 0.001
3944 reflections	Δρ_max = 0.79 e Å⁻³
263 parameters	Δρ_min = −0.75 e Å⁻³
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0020 (3)

Crystal data top

C₂₃H₂₀Br₂O₄	V = 2122 (2) Å³
M_r = 520.19	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 12.867 (7) Å	µ = 3.85 mm⁻¹
b = 18.07 (1) Å	T = 296 K
c = 9.649 (5) Å	0.34 × 0.32 × 0.28 mm
β = 108.955 (6)°

Data collection top

Bruker APEXII CCD diffractometer	3944 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	1905 reflections with I > 2σ(I)
T_min = 0.281, T_max = 0.341	R_int = 0.063
15392 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.062	0 restraints
wR(F²) = 0.207	H-atom parameters constrained
S = 1.02	Δρ_max = 0.79 e Å⁻³
3944 reflections	Δρ_min = −0.75 e Å⁻³
263 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
Br1	0.56817 (7)	0.30130 (6)	0.29797 (13)	0.1092 (5)
Br2	0.37069 (9)	0.31794 (5)	−0.00106 (10)	0.0986 (5)
C1	−0.1269 (7)	0.7137 (4)	−0.1294 (8)	0.069 (2)
H1	−0.1621	0.6777	−0.0919	0.083*
C2	−0.0059 (6)	0.7075 (3)	−0.0932 (6)	0.0509 (16)
C3	0.0495 (7)	0.7556 (4)	−0.1572 (7)	0.0658 (19)
H3	0.0096	0.7922	−0.2199	0.079*
C4	0.1583 (7)	0.7514 (4)	−0.1323 (8)	0.073 (2)
H4	0.1932	0.7846	−0.1761	0.088*
C5	0.2176 (6)	0.6962 (4)	−0.0397 (8)	0.070 (2)
H5	0.2930	0.6929	−0.0213	0.084*
C6	0.1660 (6)	0.6458 (4)	0.0260 (7)	0.0551 (16)
H6	0.2062	0.6085	0.0865	0.066*
C7	0.0548 (6)	0.6522 (3)	−0.0001 (6)	0.0511 (16)
C8	0.0522 (5)	0.5531 (3)	0.1655 (7)	0.0487 (15)
H8A	0.1057	0.5775	0.2474	0.058*
H8B	0.0905	0.5182	0.1229	0.058*
C9	−0.0317 (5)	0.5130 (3)	0.2169 (6)	0.0470 (15)
C10	−0.1419 (6)	0.5287 (4)	0.1643 (7)	0.0617 (18)
H10	−0.1676	0.5664	0.0961	0.074*
C11	−0.2162 (6)	0.4878 (5)	0.2135 (8)	0.070 (2)
H11	−0.2910	0.4979	0.1766	0.084*
C12	−0.1791 (7)	0.4340 (4)	0.3138 (8)	0.071 (2)
H12	−0.2284	0.4073	0.3465	0.085*
C13	−0.0685 (6)	0.4184 (4)	0.3684 (7)	0.0602 (17)
H13	−0.0436	0.3811	0.4378	0.072*
C14	0.0057 (5)	0.4576 (3)	0.3211 (7)	0.0487 (16)
C15	0.1611 (5)	0.3890 (3)	0.4722 (6)	0.0536 (16)
H15A	0.1381	0.3412	0.4268	0.064*
H15B	0.1347	0.3939	0.5552	0.064*
C16	0.2849 (6)	0.3950 (4)	0.5223 (7)	0.0670 (19)
H16A	0.3066	0.4437	0.5639	0.080*
H16B	0.3163	0.3586	0.5984	0.080*
C17	0.3652 (5)	0.4407 (4)	0.3435 (7)	0.0556 (17)
C18	0.3584 (6)	0.5154 (4)	0.3772 (8)	0.0675 (19)
H18	0.3226	0.5295	0.4426	0.081*
C19	0.4055 (6)	0.5681 (4)	0.3121 (9)	0.077 (2)
H19	0.4046	0.6176	0.3381	0.092*
C20	0.4531 (6)	0.5485 (5)	0.2106 (9)	0.076 (2)
H20	0.4825	0.5846	0.1656	0.091*
C21	0.4579 (6)	0.4750 (5)	0.1743 (8)	0.071 (2)
H21	0.4906	0.4622	0.1047	0.086*
C22	0.4145 (5)	0.4197 (4)	0.2401 (7)	0.0536 (16)
C23	0.4210 (6)	0.3400 (4)	0.2060 (8)	0.0657 (19)
H23	0.3725	0.3135	0.2490	0.079*
O1	−0.1819 (4)	0.7608 (3)	−0.2023 (5)	0.0824 (16)
O2	−0.0053 (3)	0.6067 (2)	0.0578 (4)	0.0549 (11)
O3	0.1171 (4)	0.4474 (2)	0.3681 (4)	0.0560 (11)
O4	0.3266 (4)	0.3834 (2)	0.4054 (5)	0.0737 (14)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Br1	0.0693 (7)	0.0994 (8)	0.1485 (10)	0.0213 (5)	0.0212 (6)	0.0112 (6)
Br2	0.1243 (9)	0.0954 (7)	0.0791 (7)	0.0014 (5)	0.0372 (6)	−0.0179 (5)
C1	0.084 (6)	0.059 (4)	0.059 (5)	0.000 (4)	0.015 (4)	0.000 (4)
C2	0.070 (5)	0.037 (3)	0.042 (4)	−0.006 (3)	0.013 (3)	−0.004 (3)
C3	0.087 (6)	0.052 (4)	0.054 (4)	−0.005 (4)	0.017 (4)	−0.002 (3)
C4	0.096 (6)	0.059 (5)	0.065 (5)	−0.022 (4)	0.027 (5)	0.010 (4)
C5	0.063 (5)	0.082 (5)	0.064 (5)	−0.015 (4)	0.019 (4)	−0.008 (4)
C6	0.058 (5)	0.051 (4)	0.049 (4)	−0.005 (3)	0.008 (3)	−0.001 (3)
C7	0.062 (5)	0.046 (4)	0.041 (4)	−0.004 (3)	0.011 (3)	−0.007 (3)
C8	0.056 (4)	0.040 (3)	0.051 (4)	0.001 (3)	0.019 (3)	0.004 (3)
C9	0.056 (4)	0.044 (4)	0.042 (4)	0.000 (3)	0.016 (3)	−0.010 (3)
C10	0.073 (5)	0.055 (4)	0.060 (4)	0.005 (4)	0.026 (4)	−0.005 (3)
C11	0.051 (4)	0.087 (5)	0.077 (5)	−0.013 (4)	0.030 (4)	−0.016 (5)
C12	0.083 (6)	0.078 (5)	0.071 (5)	−0.028 (4)	0.049 (5)	−0.019 (4)
C13	0.069 (5)	0.062 (4)	0.051 (4)	−0.008 (4)	0.021 (4)	0.002 (3)
C14	0.058 (5)	0.045 (4)	0.049 (4)	−0.005 (3)	0.025 (3)	−0.001 (3)
C15	0.071 (5)	0.056 (4)	0.034 (3)	0.001 (3)	0.017 (3)	0.006 (3)
C16	0.082 (5)	0.069 (5)	0.053 (4)	0.004 (4)	0.025 (4)	0.006 (4)
C17	0.047 (4)	0.060 (4)	0.056 (4)	0.000 (3)	0.012 (3)	0.003 (3)
C18	0.064 (5)	0.065 (5)	0.075 (5)	0.008 (4)	0.024 (4)	0.011 (4)
C19	0.064 (5)	0.057 (4)	0.086 (6)	0.004 (4)	−0.006 (5)	0.003 (4)
C20	0.063 (5)	0.082 (6)	0.079 (6)	−0.023 (4)	0.020 (4)	0.013 (4)
C21	0.061 (5)	0.088 (6)	0.064 (5)	−0.019 (4)	0.018 (4)	−0.002 (4)
C22	0.038 (4)	0.069 (4)	0.052 (4)	−0.005 (3)	0.011 (3)	−0.003 (3)
C23	0.061 (5)	0.064 (4)	0.081 (5)	0.007 (3)	0.035 (4)	0.001 (4)
O1	0.089 (4)	0.072 (3)	0.068 (3)	0.029 (3)	0.000 (3)	0.008 (3)
O2	0.058 (3)	0.050 (3)	0.057 (3)	0.002 (2)	0.019 (2)	0.014 (2)
O3	0.061 (3)	0.058 (3)	0.051 (3)	−0.002 (2)	0.021 (2)	0.011 (2)
O4	0.097 (4)	0.059 (3)	0.084 (3)	0.006 (3)	0.056 (3)	0.007 (3)

Geometric parameters (Å, º) top

Br1—C23	1.941 (7)	C12—C13	1.377 (10)
Br2—C23	1.931 (7)	C12—H12	0.9300
C1—O1	1.182 (8)	C13—C14	1.380 (8)
C1—C2	1.485 (10)	C13—H13	0.9300
C1—H1	0.9300	C14—O3	1.368 (7)
C2—C3	1.389 (9)	C15—O3	1.441 (7)
C2—C7	1.400 (8)	C15—C16	1.510 (9)
C3—C4	1.344 (10)	C15—H15A	0.9700
C3—H3	0.9300	C15—H15B	0.9700
C4—C5	1.389 (10)	C16—O4	1.414 (7)
C4—H4	0.9300	C16—H16A	0.9700
C5—C6	1.395 (9)	C16—H16B	0.9700
C5—H5	0.9300	C17—O4	1.367 (7)
C6—C7	1.376 (9)	C17—C18	1.397 (9)
C6—H6	0.9300	C17—C22	1.397 (9)
C7—O2	1.366 (7)	C18—C19	1.385 (10)
C8—O2	1.437 (7)	C18—H18	0.9300
C8—C9	1.510 (8)	C19—C20	1.361 (11)
C8—H8A	0.9700	C19—H19	0.9300
C8—H8B	0.9700	C20—C21	1.379 (11)
C9—C10	1.372 (9)	C20—H20	0.9300
C9—C14	1.390 (8)	C21—C22	1.394 (9)
C10—C11	1.408 (9)	C21—H21	0.9300
C10—H10	0.9300	C22—C23	1.486 (9)
C11—C12	1.344 (10)	C23—H23	0.9800
C11—H11	0.9300

O1—C1—C2	124.9 (7)	O3—C14—C13	125.8 (6)
O1—C1—H1	117.5	O3—C14—C9	114.6 (5)
C2—C1—H1	117.5	C13—C14—C9	119.7 (6)
C3—C2—C7	118.2 (7)	O3—C15—C16	107.8 (5)
C3—C2—C1	119.9 (6)	O3—C15—H15A	110.1
C7—C2—C1	121.9 (6)	C16—C15—H15A	110.1
C4—C3—C2	122.7 (7)	O3—C15—H15B	110.1
C4—C3—H3	118.7	C16—C15—H15B	110.1
C2—C3—H3	118.7	H15A—C15—H15B	108.5
C3—C4—C5	118.6 (7)	O4—C16—C15	111.6 (5)
C3—C4—H4	120.7	O4—C16—H16A	109.3
C5—C4—H4	120.7	C15—C16—H16A	109.3
C4—C5—C6	121.2 (7)	O4—C16—H16B	109.3
C4—C5—H5	119.4	C15—C16—H16B	109.3
C6—C5—H5	119.4	H16A—C16—H16B	108.0
C7—C6—C5	118.8 (6)	O4—C17—C18	124.7 (6)
C7—C6—H6	120.6	O4—C17—C22	114.9 (6)
C5—C6—H6	120.6	C18—C17—C22	120.4 (6)
O2—C7—C6	124.6 (6)	C19—C18—C17	119.3 (7)
O2—C7—C2	114.9 (6)	C19—C18—H18	120.4
C6—C7—C2	120.5 (6)	C17—C18—H18	120.4
O2—C8—C9	107.8 (5)	C20—C19—C18	120.8 (7)
O2—C8—H8A	110.1	C20—C19—H19	119.6
C9—C8—H8A	110.1	C18—C19—H19	119.6
O2—C8—H8B	110.1	C19—C20—C21	120.1 (7)
C9—C8—H8B	110.1	C19—C20—H20	119.9
H8A—C8—H8B	108.5	C21—C20—H20	119.9
C10—C9—C14	119.3 (6)	C20—C21—C22	121.1 (7)
C10—C9—C8	122.8 (6)	C20—C21—H21	119.5
C14—C9—C8	117.8 (5)	C22—C21—H21	119.5
C9—C10—C11	120.0 (7)	C17—C22—C21	118.2 (7)
C9—C10—H10	120.0	C17—C22—C23	119.5 (6)
C11—C10—H10	120.0	C21—C22—C23	122.3 (6)
C12—C11—C10	120.1 (7)	C22—C23—Br2	113.9 (5)
C12—C11—H11	120.0	C22—C23—Br1	111.4 (5)
C10—C11—H11	120.0	Br2—C23—Br1	110.4 (3)
C11—C12—C13	120.3 (6)	C22—C23—H23	106.9
C11—C12—H12	119.8	Br2—C23—H23	106.9
C13—C12—H12	119.8	Br1—C23—H23	106.9
C14—C13—C12	120.6 (7)	C7—O2—C8	118.4 (5)
C14—C13—H13	119.7	C14—O3—C15	117.5 (5)
C12—C13—H13	119.7	C17—O4—C16	121.6 (5)

O1—C1—C2—C3	−6.0 (10)	O3—C15—C16—O4	−63.5 (7)
O1—C1—C2—C7	176.8 (6)	O4—C17—C18—C19	176.8 (6)
C7—C2—C3—C4	−0.6 (10)	C22—C17—C18—C19	−3.0 (10)
C1—C2—C3—C4	−178.0 (6)	C17—C18—C19—C20	3.4 (11)
C2—C3—C4—C5	0.6 (10)	C18—C19—C20—C21	−1.9 (11)
C3—C4—C5—C6	0.3 (10)	C19—C20—C21—C22	0.0 (11)
C4—C5—C6—C7	−1.1 (10)	O4—C17—C22—C21	−178.7 (6)
C5—C6—C7—O2	−179.8 (5)	C18—C17—C22—C21	1.1 (9)
C5—C6—C7—C2	1.1 (9)	O4—C17—C22—C23	0.1 (9)
C3—C2—C7—O2	−179.5 (5)	C18—C17—C22—C23	179.9 (6)
C1—C2—C7—O2	−2.2 (8)	C20—C21—C22—C17	0.4 (10)
C3—C2—C7—C6	−0.3 (9)	C20—C21—C22—C23	−178.3 (7)
C1—C2—C7—C6	177.0 (6)	C17—C22—C23—Br2	130.6 (5)
O2—C8—C9—C10	0.0 (8)	C21—C22—C23—Br2	−50.7 (8)
O2—C8—C9—C14	179.3 (5)	C17—C22—C23—Br1	−103.8 (6)
C14—C9—C10—C11	−1.3 (9)	C21—C22—C23—Br1	75.0 (7)
C8—C9—C10—C11	178.0 (5)	C6—C7—O2—C8	6.8 (8)
C9—C10—C11—C12	1.0 (10)	C2—C7—O2—C8	−174.1 (5)
C10—C11—C12—C13	−0.4 (10)	C9—C8—O2—C7	177.1 (4)
C11—C12—C13—C14	0.0 (10)	C13—C14—O3—C15	2.5 (8)
C12—C13—C14—O3	179.5 (6)	C9—C14—O3—C15	−177.8 (5)
C12—C13—C14—C9	−0.3 (9)	C16—C15—O3—C14	−172.6 (5)
C10—C9—C14—O3	−178.8 (5)	C18—C17—O4—C16	−6.4 (10)
C8—C9—C14—O3	1.8 (7)	C22—C17—O4—C16	173.5 (5)
C10—C9—C14—C13	1.0 (9)	C15—C16—O4—C17	105.9 (7)
C8—C9—C14—C13	−178.4 (5)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C1—H1···O2	0.93	2.42	2.753 (9)	101
C10—H10···O2	0.93	2.35	2.710 (8)	102
C23—H23···O4	0.98	2.19	2.700 (8)	111
C5—H5···Br1ⁱ	0.93	3.03	3.529 (7)	116

Symmetry code: (i) −x+1, y+1/2, −z+1/2.

Experimental details

Crystal data
Chemical formula	C₂₃H₂₀Br₂O₄
M_r	520.19
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	296
a, b, c (Å)	12.867 (7), 18.07 (1), 9.649 (5)
β (°)	108.955 (6)
V (Å³)	2122 (2)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	3.85
Crystal size (mm)	0.34 × 0.32 × 0.28

Data collection
Diffractometer	Bruker APEXII CCD diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.281, 0.341
No. of measured, independent and observed [I > 2σ(I)] reflections	15392, 3944, 1905
R_int	0.063
(sin θ/λ)_max (Å⁻¹)	0.606

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.062, 0.207, 1.02
No. of reflections	3944
No. of parameters	263
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.79, −0.75

Computer programs: APEX2 (Bruker, 2007), SAINT (Bruker, 2007), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C1—H1···O2	0.93	2.42	2.753 (9)	101
C10—H10···O2	0.93	2.35	2.710 (8)	102
C23—H23···O4	0.98	2.19	2.700 (8)	111
C5—H5···Br1ⁱ	0.93	3.03	3.529 (7)	116

Symmetry code: (i) −x+1, y+1/2, −z+1/2.

Acknowledgements

The authors acknowledge the Fundamental Research Funds for the Central Universities (lzujbky-2010-43) and the Research Foundation for Young Teachers Possessing a Doctoral Degree of Lanzhou University for financial support.

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