4-(7-Acet­oxy-6-meth­oxy-4-methyl-2-oxo-2H-chromen-3-yl)phenyl acetate

Jiang, H.; Xia, P.; Zhang, Q.

doi:10.1107/S1600536808012890

organic compounds

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ISSN: 2056-9890

Volume 64| Part 7| July 2008| Page o1230

doi:10.1107/S1600536808012890

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4-(7-Acetoxy-6-methoxy-4-methyl-2-oxo-2H-chromen-3-yl)phenyl acetate

Hao Jiang,^a Peng Xia ^a and Qian Zhang ^a ^*

^aDepartment of Medicinal Chemistry, School of Pharmacy, Fudan University, Shanghai 200032, People's Republic of China
^*Correspondence e-mail: zhangqian511@shmu.edu.cn

(Received 29 April 2008; accepted 1 May 2008; online 7 June 2008)

The title compound, C₂₁H₁₈O₇, is an important intermediate in the synthesis of 3-(4-hydroxyphenyl)-4-methyl-6-methoxy-7-hydroxycoumarin, which is a nonsteroidal analogue of 2-methoxyestradiol (2-ME). The substituent benzene ring is not in the same plane as the coumarin ring system, with a dihedral angle of 66.88 (10)°. There are some weak intermolecular C—H⋯O interactions. One carbonyl O atom is disordered over two sites, with occupancies of 0.6 and 0.4.

Related literature

For related literature, see: Gibanananda et al. (2006 ); Sutherland et al. (2007 ).

Experimental

Crystal data

C₂₁H₁₈O₇
M_r = 382.35
Triclinic, $[P \overline 1]$
a = 8.142 (3) Å
b = 11.167 (4) Å
c = 11.756 (4) Å
α = 65.130 (4)°
β = 75.392 (4)°
γ = 79.055 (4)°
V = 934.1 (5) Å³
Z = 2
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 293 (2) K
0.15 × 0.12 × 0.04 mm

Data collection

Bruker SMART APEX CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ) T_min = 0.985, T_max = 0.996
3893 measured reflections
3245 independent reflections
2279 reflections with I > 2σ(I)
R_int = 0.031

Refinement

R[F² > 2σ(F²)] = 0.074
wR(F²) = 0.254
S = 1.09
3245 reflections
266 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 0.28 e Å⁻³
Δρ_min = −0.50 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C20—H20B⋯O2ⁱ	0.96	2.47	3.362 (4)	154
C20—H20C⋯O4Bⁱ	0.96	2.55	3.297 (9)	134
C11—H11B⋯O7ⁱⁱ	0.96	2.74	3.349 (4)	122
C13—H13⋯O2ⁱⁱⁱ	0.93	2.74	3.331 (4)	122
C19—H19A⋯O7ⁱⁱⁱ	0.96	2.50	3.392 (5)	154
C17—H17⋯O2^iv	0.93	2.66	3.246 (3)	122
Symmetry codes: (i) x, y-1, z; (ii) -x, -y, -z; (iii) -x, -y+1, -z; (iv) -x+1, -y+1, -z.

Data collection: SMART (Bruker, 2000 ); cell refinement: SMART; data reduction: SAINT (Bruker, 2000); 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/S1600536808012890/cf2199sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808012890/cf2199Isup2.hkl

checkCIF report

Comment top

2-ME, an endogenous metabolite of estrogen, was proved to be a potent antitumor and antiangiogenic compound (Gibanananda et al., 2006). Currently 2-ME is in phase I–III clinical trials for treating a variety of solid cancers, especially breast cancer, prostate cancer and multiple myeloma (Sutherland et al., 2007). Based on the structure and the bioactivity of 2-ME, 3-(p-hydroxyphenyl)-4-methyl-6-methoxyl-7-hydroxycoumarin, an non-steroidal analog of 2-ME, was designed, synthesized and evaluated on Human Umbilical Vein Endothelial Cells (HUVEC). The compound showed higher activity and much lower toxicity (EC₅₀ = 5.69 µM; TI = 45.01) than 2-ME (EC₅₀ = 8.59 µM; TI = 8.25) in the biological assay. Here we report the crystal structure of 3-(p-acetoxyphenyl)-4-methyl-6-methoxyl-7-acetoxycoumarin, which is an important intermediate in the synthesis of 3-(p-hydroxyphenyl)-4-methyl-6-methoxyl-7-hydroxycoumarin. The molecular structure of (I) is illustrated in Fig.1. The coumarin ring system (C1—C10) is essentially planar, with a mean deviation of 0.0153 Å from the least-squares plane defined by the ten constituent atoms. The coumarin ring system and the 3-aryl ring make a dihedral angle of 66.88 (10)°. The fact that the of C3—C12 bond [length 1.480 (4) Å] is a single bond also confirms that the coumarin ring system and the 3-substituent are not conjugated. The molecular packing (Fig. 2) is stabilized by weak intermolecular C—H···O hydrogen bonds.

Related literature top

For related literature, see: Gibanananda et al. (2006); Sutherland et al. (2007).

Experimental top

A mixture of 1-(2,4-dihydroxyl-5-methoxyphenyl)ethanone (300 mg, 1.65 mmol), 4-hydroxyphenylacetic acid (501 mg, 3.29 mmol), Et₃N (6 ml) and Ac₂O (10 ml) was refluxed for 10 h. After cooling, the mixture was poured into 2 N HCl (20 ml) and extracted with acetyl acetate. The organic layer was dried over Na₂SO₄, filtered, and concentrated under reduced pressure to give a yellow oil, which was purified via chromatography on silica gel column with petroleum ether/acetone (10:3) as eluent. The title compound was recrystallized from acetyl acetate to give colorless crystals for the single-crystal X-ray diffraction analysis.

Computing details top

Data collection: SMART (Bruker, 2000); cell refinement: SMART (Bruker, 2000); data reduction: SAINT (Bruker, 2000); 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 (I), with atom labels and 30% probability displacement ellipsoids for non-H atoms. The minor disorder component is not shown.
	Fig. 2. Packing diagram, viewed down the b axis.

4-(7-Acetoxy-6-methoxy-4-methyl-2-oxo-2H-chromen-3-yl)phenyl acetate top

Crystal data top

C₂₁H₁₈O₇	Z = 2
M_r = 382.35	F(000) = 400
Triclinic, P1	D_x = 1.359 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 8.142 (3) Å	Cell parameters from 954 reflections
b = 11.167 (4) Å	θ = 2.6–26.3°
c = 11.756 (4) Å	µ = 0.10 mm⁻¹
α = 65.130 (4)°	T = 293 K
β = 75.392 (4)°	Sheet, colorless
γ = 79.055 (4)°	0.15 × 0.12 × 0.04 mm
V = 934.1 (5) Å³

Data collection top

Bruker SMART APEX CCD area-detector diffractometer	3245 independent reflections
Radiation source: fine-focus sealed tube	2279 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.031
ϕ and ω scans	θ_max = 25.1°, θ_min = 2.0°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −9→9
T_min = 0.985, T_max = 0.996	k = −13→10
3893 measured reflections	l = −13→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)] = 0.074	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.254	H-atom parameters constrained
S = 1.10	w = 1/[σ²(F_o²) + (0.1741P)²] where P = (F_o² + 2F_c²)/3
3245 reflections	(Δ/σ)_max < 0.001
266 parameters	Δρ_max = 0.28 e Å⁻³
1 restraint	Δρ_min = −0.50 e Å⁻³

Crystal data top

C₂₁H₁₈O₇	γ = 79.055 (4)°
M_r = 382.35	V = 934.1 (5) Å³
Triclinic, P1	Z = 2
a = 8.142 (3) Å	Mo Kα radiation
b = 11.167 (4) Å	µ = 0.10 mm⁻¹
c = 11.756 (4) Å	T = 293 K
α = 65.130 (4)°	0.15 × 0.12 × 0.04 mm
β = 75.392 (4)°

Data collection top

Bruker SMART APEX CCD area-detector diffractometer	3245 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	2279 reflections with I > 2σ(I)
T_min = 0.985, T_max = 0.996	R_int = 0.031
3893 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.074	1 restraint
wR(F²) = 0.254	H-atom parameters constrained
S = 1.10	Δρ_max = 0.28 e Å⁻³
3245 reflections	Δρ_min = −0.50 e Å⁻³
266 parameters

Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'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	Occ. (<1)
O1	0.3185 (3)	0.17959 (18)	0.16190 (17)	0.0502 (6)
O2	0.3094 (3)	0.3939 (2)	0.1010 (2)	0.0586 (6)
O3	0.2256 (3)	0.8533 (2)	−0.4110 (2)	0.0687 (7)
O5	0.2670 (3)	−0.27608 (18)	0.10771 (19)	0.0563 (6)
O6	0.3460 (2)	−0.28758 (18)	0.31855 (17)	0.0507 (6)
O7	0.0661 (3)	−0.3060 (2)	0.3850 (2)	0.0736 (7)
C2	0.2997 (4)	0.3052 (3)	0.0710 (3)	0.0461 (7)
C3	0.2680 (3)	0.3215 (3)	−0.0519 (3)	0.0422 (7)
C4	0.2529 (3)	0.2128 (3)	−0.0733 (2)	0.0405 (6)
C5	0.2552 (3)	−0.0362 (3)	0.0142 (2)	0.0425 (7)
H5	0.2329	−0.0317	−0.0613	0.051*
C6	0.2753 (3)	−0.1569 (3)	0.1113 (3)	0.0442 (7)
C7	0.3133 (3)	−0.1642 (3)	0.2232 (3)	0.0440 (7)
C8	0.3266 (4)	−0.0521 (3)	0.2393 (3)	0.0481 (7)
H8	0.3507	−0.0578	0.3148	0.058*
C9	0.3036 (3)	0.0699 (3)	0.1407 (2)	0.0413 (6)
C10	0.2678 (3)	0.0826 (3)	0.0268 (2)	0.0399 (6)
C11	0.2208 (4)	0.2260 (3)	−0.1983 (3)	0.0527 (8)
H11A	0.2364	0.3147	−0.2601	0.079*
H11B	0.1061	0.2074	−0.1871	0.079*
H11C	0.2992	0.1644	−0.2276	0.079*
C12	0.2578 (3)	0.4597 (3)	−0.1475 (3)	0.0444 (7)
C13	0.1053 (4)	0.5256 (3)	−0.1852 (3)	0.0592 (8)
H13	0.0075	0.4810	−0.1518	0.071*
C14	0.0962 (4)	0.6549 (3)	−0.2704 (3)	0.0641 (9)
H14	−0.0067	0.6966	−0.2953	0.077*
C15	0.2384 (4)	0.7232 (3)	−0.3192 (3)	0.0524 (8)
C16	0.3906 (4)	0.6615 (3)	−0.2841 (3)	0.0540 (8)
H16	0.4875	0.7072	−0.3181	0.065*
C17	0.3995 (4)	0.5314 (3)	−0.1982 (3)	0.0497 (7)
H17	0.5028	0.4907	−0.1737	0.060*
C18	0.2305 (6)	0.9555 (4)	−0.3829 (4)	0.0864 (13)
O4A	0.1775 (16)	0.9331 (7)	−0.2672 (6)	0.159 (4)	0.55
O4B	0.3254 (11)	0.9405 (7)	−0.3076 (8)	0.094 (2)	0.45
C19	0.2078 (6)	1.0852 (3)	−0.4860 (4)	0.0876 (12)
H19A	0.1643	1.1509	−0.4506	0.131*
H19B	0.1287	1.0822	−0.5329	0.131*
H19C	0.3155	1.1075	−0.5424	0.131*
C20	0.2417 (4)	−0.2736 (3)	−0.0087 (3)	0.0571 (8)
H20A	0.1307	−0.2306	−0.0234	0.086*
H20B	0.2502	−0.3627	−0.0032	0.086*
H20C	0.3270	−0.2258	−0.0781	0.086*
C21	0.2086 (4)	−0.3556 (3)	0.3919 (3)	0.0515 (8)
C22	0.2624 (5)	−0.4899 (3)	0.4777 (3)	0.0720 (10)
H22A	0.2921	−0.4860	0.5500	0.108*
H22B	0.3596	−0.5265	0.4327	0.108*
H22C	0.1707	−0.5449	0.5065	0.108*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0708 (14)	0.0396 (11)	0.0404 (11)	−0.0112 (9)	−0.0212 (9)	−0.0075 (9)
O2	0.0779 (15)	0.0445 (12)	0.0597 (13)	−0.0139 (10)	−0.0268 (11)	−0.0153 (10)
O3	0.113 (2)	0.0374 (12)	0.0452 (12)	−0.0105 (12)	−0.0248 (12)	0.0010 (9)
O5	0.0827 (15)	0.0348 (11)	0.0463 (12)	−0.0121 (10)	−0.0177 (10)	−0.0054 (9)
O6	0.0515 (12)	0.0402 (11)	0.0424 (11)	−0.0096 (9)	−0.0125 (9)	0.0050 (9)
O7	0.0529 (14)	0.0680 (16)	0.0697 (16)	−0.0088 (12)	−0.0070 (11)	0.0002 (12)
C2	0.0489 (16)	0.0437 (16)	0.0429 (16)	−0.0153 (12)	−0.0139 (12)	−0.0068 (13)
C3	0.0420 (15)	0.0379 (15)	0.0410 (15)	−0.0089 (11)	−0.0109 (12)	−0.0064 (12)
C4	0.0398 (14)	0.0402 (15)	0.0345 (14)	−0.0074 (11)	−0.0094 (11)	−0.0052 (11)
C5	0.0492 (16)	0.0401 (15)	0.0345 (14)	−0.0087 (12)	−0.0120 (12)	−0.0072 (12)
C6	0.0464 (15)	0.0364 (15)	0.0426 (15)	−0.0107 (12)	−0.0077 (12)	−0.0062 (12)
C7	0.0437 (15)	0.0378 (14)	0.0361 (14)	−0.0081 (11)	−0.0069 (11)	0.0005 (11)
C8	0.0555 (17)	0.0502 (17)	0.0336 (14)	−0.0113 (14)	−0.0154 (12)	−0.0053 (12)
C9	0.0469 (15)	0.0372 (14)	0.0371 (14)	−0.0089 (11)	−0.0092 (11)	−0.0093 (11)
C10	0.0402 (14)	0.0402 (15)	0.0336 (14)	−0.0096 (11)	−0.0089 (11)	−0.0057 (11)
C11	0.073 (2)	0.0404 (15)	0.0380 (15)	−0.0088 (14)	−0.0198 (14)	−0.0027 (12)
C12	0.0499 (16)	0.0397 (15)	0.0401 (15)	−0.0092 (12)	−0.0122 (12)	−0.0084 (12)
C13	0.0510 (17)	0.0442 (17)	0.065 (2)	−0.0106 (14)	−0.0162 (15)	0.0009 (14)
C14	0.0596 (19)	0.0531 (19)	0.063 (2)	−0.0022 (15)	−0.0246 (16)	−0.0007 (15)
C15	0.072 (2)	0.0405 (16)	0.0363 (15)	−0.0119 (14)	−0.0124 (14)	−0.0031 (12)
C16	0.0615 (19)	0.0416 (16)	0.0510 (17)	−0.0156 (14)	−0.0083 (14)	−0.0075 (13)
C17	0.0490 (16)	0.0442 (16)	0.0510 (17)	−0.0111 (13)	−0.0130 (13)	−0.0092 (13)
C18	0.153 (4)	0.045 (2)	0.057 (2)	−0.003 (2)	−0.040 (3)	−0.0074 (16)
O4A	0.341 (14)	0.060 (4)	0.057 (4)	0.018 (7)	−0.045 (6)	−0.017 (3)
O4B	0.162 (7)	0.044 (3)	0.087 (5)	−0.015 (4)	−0.069 (5)	−0.009 (3)
C19	0.128 (4)	0.0412 (19)	0.070 (2)	−0.002 (2)	−0.020 (2)	−0.0011 (16)
C20	0.071 (2)	0.0475 (17)	0.0543 (18)	−0.0161 (14)	−0.0085 (15)	−0.0191 (14)
C21	0.0548 (19)	0.0492 (17)	0.0397 (16)	−0.0136 (14)	−0.0073 (13)	−0.0047 (13)
C22	0.077 (2)	0.0501 (19)	0.061 (2)	−0.0128 (17)	−0.0088 (17)	0.0060 (16)

Geometric parameters (Å, º) top

O1—C2	1.369 (3)	C11—H11C	0.960
O1—C9	1.380 (3)	C12—C17	1.389 (4)
O2—C2	1.205 (3)	C12—C13	1.392 (4)
O3—C18	1.324 (4)	C13—C14	1.369 (4)
O3—C15	1.402 (3)	C13—H13	0.930
O5—C6	1.364 (3)	C14—C15	1.372 (5)
O5—C20	1.423 (4)	C14—H14	0.930
O6—C21	1.363 (3)	C15—C16	1.369 (5)
O6—C7	1.392 (3)	C16—C17	1.378 (4)
O7—C21	1.194 (4)	C16—H16	0.930
C2—C3	1.461 (4)	C17—H17	0.930
C3—C4	1.371 (4)	C18—O4A	1.248 (7)
C3—C12	1.480 (4)	C18—O4B	1.257 (7)
C4—C10	1.442 (3)	C18—C19	1.461 (5)
C4—C11	1.498 (4)	C19—H19A	0.960
C5—C6	1.364 (4)	C19—H19B	0.960
C5—C10	1.421 (4)	C19—H19C	0.960
C5—H5	0.930	C20—H20A	0.960
C6—C7	1.392 (4)	C20—H20B	0.960
C7—C8	1.369 (4)	C20—H20C	0.960
C8—C9	1.386 (4)	C21—C22	1.470 (4)
C8—H8	0.930	C22—H22A	0.960
C9—C10	1.386 (4)	C22—H22B	0.960
C11—H11A	0.960	C22—H22C	0.960
C11—H11B	0.960

C2—O1—C9	121.4 (2)	C14—C13—H13	119.3
C18—O3—C15	120.8 (2)	C12—C13—H13	119.3
C6—O5—C20	116.9 (2)	C13—C14—C15	120.2 (3)
C21—O6—C7	116.7 (2)	C13—C14—H14	119.9
O2—C2—O1	115.9 (2)	C15—C14—H14	119.9
O2—C2—C3	125.5 (3)	C16—C15—C14	120.0 (3)
O1—C2—C3	118.6 (2)	C16—C15—O3	121.5 (3)
C4—C3—C2	120.2 (2)	C14—C15—O3	118.4 (3)
C4—C3—C12	124.4 (2)	C15—C16—C17	119.7 (3)
C2—C3—C12	115.4 (2)	C15—C16—H16	120.1
C3—C4—C10	119.3 (2)	C17—C16—H16	120.1
C3—C4—C11	121.6 (2)	C16—C17—C12	121.6 (3)
C10—C4—C11	119.1 (2)	C16—C17—H17	119.2
C6—C5—C10	121.0 (2)	C12—C17—H17	119.2
C6—C5—H5	119.5	O4A—C18—O3	113.0 (5)
C10—C5—H5	119.5	O4B—C18—O3	117.6 (5)
O5—C6—C5	125.2 (2)	O4A—C18—C19	123.9 (5)
O5—C6—C7	115.1 (2)	O4B—C18—C19	119.1 (5)
C5—C6—C7	119.6 (2)	O3—C18—C19	114.7 (3)
C8—C7—O6	119.0 (2)	C18—C19—H19A	109.5
C8—C7—C6	121.2 (2)	C18—C19—H19B	109.5
O6—C7—C6	119.7 (2)	H19A—C19—H19B	109.5
C7—C8—C9	118.6 (2)	C18—C19—H19C	109.5
C7—C8—H8	120.7	H19A—C19—H19C	109.5
C9—C8—H8	120.7	H19B—C19—H19C	109.5
O1—C9—C10	121.3 (2)	O5—C20—H20A	109.5
O1—C9—C8	116.2 (2)	O5—C20—H20B	109.5
C10—C9—C8	122.5 (2)	H20A—C20—H20B	109.5
C9—C10—C5	117.0 (2)	O5—C20—H20C	109.5
C9—C10—C4	119.1 (2)	H20A—C20—H20C	109.5
C5—C10—C4	123.8 (2)	H20B—C20—H20C	109.5
C4—C11—H11A	109.5	O7—C21—O6	121.7 (3)
C4—C11—H11B	109.5	O7—C21—C22	127.3 (3)
H11A—C11—H11B	109.5	O6—C21—C22	111.0 (3)
C4—C11—H11C	109.5	C21—C22—H22A	109.5
H11A—C11—H11C	109.5	C21—C22—H22B	109.5
H11B—C11—H11C	109.5	H22A—C22—H22B	109.5
C17—C12—C13	117.1 (3)	C21—C22—H22C	109.5
C17—C12—C3	120.9 (2)	H22A—C22—H22C	109.5
C13—C12—C3	121.9 (2)	H22B—C22—H22C	109.5
C14—C13—C12	121.4 (3)

C9—O1—C2—O2	177.5 (2)	C8—C9—C10—C4	−177.3 (2)
C9—O1—C2—C3	−1.8 (4)	C6—C5—C10—C9	0.9 (4)
O2—C2—C3—C4	−177.4 (3)	C6—C5—C10—C4	178.1 (2)
O1—C2—C3—C4	1.8 (4)	C3—C4—C10—C9	−2.5 (4)
O2—C2—C3—C12	3.8 (4)	C11—C4—C10—C9	177.7 (2)
O1—C2—C3—C12	−177.0 (2)	C3—C4—C10—C5	−179.6 (2)
C2—C3—C4—C10	0.3 (4)	C11—C4—C10—C5	0.6 (4)
C12—C3—C4—C10	179.0 (2)	C4—C3—C12—C17	−113.2 (3)
C2—C3—C4—C11	−179.9 (2)	C2—C3—C12—C17	65.6 (4)
C12—C3—C4—C11	−1.2 (4)	C4—C3—C12—C13	70.4 (4)
C20—O5—C6—C5	2.5 (4)	C2—C3—C12—C13	−110.8 (3)
C20—O5—C6—C7	−175.2 (2)	C17—C12—C13—C14	1.2 (5)
C10—C5—C6—O5	−179.4 (2)	C3—C12—C13—C14	177.8 (3)
C10—C5—C6—C7	−1.8 (4)	C12—C13—C14—C15	−1.0 (5)
C21—O6—C7—C8	106.7 (3)	C13—C14—C15—C16	0.9 (5)
C21—O6—C7—C6	−76.1 (3)	C13—C14—C15—O3	176.9 (3)
O5—C6—C7—C8	179.6 (2)	C18—O3—C15—C16	−74.4 (5)
C5—C6—C7—C8	1.7 (4)	C18—O3—C15—C14	109.6 (4)
O5—C6—C7—O6	2.5 (4)	C14—C15—C16—C17	−1.0 (5)
C5—C6—C7—O6	−175.4 (2)	O3—C15—C16—C17	−176.9 (3)
O6—C7—C8—C9	176.3 (2)	C15—C16—C17—C12	1.1 (5)
C6—C7—C8—C9	−0.8 (4)	C13—C12—C17—C16	−1.2 (4)
C2—O1—C9—C10	−0.4 (4)	C3—C12—C17—C16	−177.8 (3)
C2—O1—C9—C8	179.4 (2)	C15—O3—C18—O4A	−27.7 (9)
C7—C8—C9—O1	−180.0 (2)	C15—O3—C18—O4B	35.1 (8)
C7—C8—C9—C10	−0.1 (4)	C15—O3—C18—C19	−177.3 (3)
O1—C9—C10—C5	179.9 (2)	C7—O6—C21—O7	−8.4 (4)
C8—C9—C10—C5	0.0 (4)	C7—O6—C21—C22	173.1 (3)
O1—C9—C10—C4	2.6 (4)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C20—H20B···O2ⁱ	0.96	2.47	3.362 (4)	154
C20—H20C···O4Bⁱ	0.96	2.55	3.297 (9)	134
C11—H11B···O7ⁱⁱ	0.96	2.74	3.349 (4)	122
C13—H13···O2ⁱⁱⁱ	0.93	2.74	3.331 (4)	122
C19—H19A···O7ⁱⁱⁱ	0.96	2.50	3.392 (5)	154
C17—H17···O2^iv	0.93	2.66	3.246 (3)	122

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

Experimental details

Crystal data
Chemical formula	C₂₁H₁₈O₇
M_r	382.35
Crystal system, space group	Triclinic, P1
Temperature (K)	293
a, b, c (Å)	8.142 (3), 11.167 (4), 11.756 (4)
α, β, γ (°)	65.130 (4), 75.392 (4), 79.055 (4)
V (Å³)	934.1 (5)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.10
Crystal size (mm)	0.15 × 0.12 × 0.04

Data collection
Diffractometer	Bruker SMART APEX CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.985, 0.996
No. of measured, independent and observed [I > 2σ(I)] reflections	3893, 3245, 2279
R_int	0.031
(sin θ/λ)_max (Å⁻¹)	0.597

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.074, 0.254, 1.10
No. of reflections	3245
No. of parameters	266
No. of restraints	1
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.28, −0.50

Computer programs: SMART (Bruker, 2000), SAINT (Bruker, 2000), 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
C20—H20B···O2ⁱ	0.96	2.47	3.362 (4)	153.9
C20—H20C···O4Bⁱ	0.96	2.55	3.297 (9)	134.3
C11—H11B···O7ⁱⁱ	0.96	2.74	3.349 (4)	122.2
C13—H13···O2ⁱⁱⁱ	0.93	2.74	3.331 (4)	122.1
C19—H19A···O7ⁱⁱⁱ	0.96	2.50	3.392 (5)	153.6
C17—H17···O2^iv	0.93	2.66	3.246 (3)	121.9

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

Acknowledgements

This work was financed by the National Natural Science Foundation of China (grant No. 30500631, awarded to Qian Zhang) and the Postgraduate Innovative Research Foundation of Fudan University (grant awarded to Hao Jiang). The authors acknowledge Professor Minqin Chen, Center of Analysis and Measurement, Fudan University, for his kind help with the data analysis and his professional advice.

References

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