Methyl 2-(7-benz­yloxy-1-naphth­yl)-2-oxoacetate

Fun, H.-K.; Chantrapromma, S.; Li, S.-X.; Li, H.-M.

doi:10.1107/S160053680801982X

organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 64| Part 8| August 2008| Page o1409

doi:10.1107/S160053680801982X

Open

access

Methyl 2-(7-benzyloxy-1-naphthyl)-2-oxoacetate

Hoong-Kun Fun,^a ^* Suchada Chantrapromma,^b ‡ Shu-Xian Li ^c § and Hua-Min Li ^c

^aX-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia, ^bCrystal Materials Research Unit, Department of Chemistry, Faculty of Science, Prince of Songkla University, Hat-Yai, Songkhla 90112, Thailand, and ^cDepartment of Chemistry, Beijing Normal University, Beijing 100875, People's Republic of China
^*Correspondence e-mail: hkfun@usm.my

(Received 25 June 2008; accepted 29 June 2008; online 5 July 2008)

In the crystal structure of the title compound, C₂₀H₁₆O₄, the naphthalene ring system makes dihedral angles of 43.79 (7) and 83.70 (9)°, respectively, with the mean planes of the phenyl ring and the acetate unit. C—H⋯π interactions involving all the aromatic six-membered rings are observed. The molecules are stacked into columns along the a axis and adjacent columns are linked by weak C—H⋯O interactions.

Related literature

For related literature on hydrogen-bond motifs, see: Bernstein et al. (1995 ). For values of bond lengths, see: Allen et al. (1987 ). For related literature on bioactivities of compounds containing aromatic rings, see, for example: Hartwig (1998 ); Knepper et al. (2004 ); Kunz et al. (2003 ); Ley & Thomas (2003 ); Palucki et al. (1997 ).

Experimental

Crystal data

C₂₀H₁₆O₄
M_r = 320.33
Orthorhombic, P 2₁ 2₁ 2₁
a = 5.6145 (3) Å
b = 15.7422 (8) Å
c = 17.3843 (8) Å
V = 1536.50 (13) Å³
Z = 4
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 100.0 (1) K
0.58 × 0.32 × 0.10 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ) T_min = 0.946, T_max = 0.991
17379 measured reflections
2575 independent reflections
2380 reflections with I > 2σ(I)
R_int = 0.038

Refinement

R[F² > 2σ(F²)] = 0.034
wR(F²) = 0.100
S = 1.08
2575 reflections
218 parameters
H-atom parameters constrained
Δρ_max = 0.29 e Å⁻³
Δρ_min = −0.17 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

Cg1, Cg2 and Cg3 are the centroids of the C1–C4/C9–C10, C4–C9 and C12–C17 rings, respectively.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C10—H10A⋯O2	0.93	2.28	2.896 (2)	124
C14—H14A⋯O2ⁱ	0.93	2.52	3.315 (2)	144
C20—H20B⋯O1ⁱⁱ	0.96	2.53	3.458 (2)	163
C7—H7A⋯Cg2ⁱⁱⁱ	0.93	3.15	3.8529 (18)	134
C13—H13A⋯Cg3^iv	0.93	3.13	3.8070 (19)	132
C17—H17A⋯Cg1^v	0.93	3.12	4.0033 (17)	159
Symmetry codes: (i) $[x-{\script{1\over 2}}, -y+{\script{3\over 2}}, -z+1]$ ; (ii) $[-x+{\script{3\over 2}}, -y+1, z-{\script{1\over 2}}]$ ; (iii) $[-x, y+{\script{1\over 2}}, -z+{\script{3\over 2}}]$ ; (iv) $[-x, y+{\script{3\over 2}}, -z+{\script{3\over 2}}]$ ; (v) x-1, y, z.

Data collection: APEX2 (Bruker, 2005); cell refinement: APEX2; data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2003 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S160053680801982X/is2310sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S160053680801982X/is2310Isup2.hkl

checkCIF report

Comment top

Ether compounds containing aromatic rings are useful intermediates in organic synthesis and are found in a large number of biologically active compounds. Some ethers containing aromatic units such as perrottetines, riccardin B and marchantin quinone exert considerable pharmacological activities, such as influencing blood coagulation. Others found usage as antifungal peperazinomycin and the glycopeptide antibiotics vancomycin (Hartwig, 1998; Knepper et al., 2004; Kunz et al., 2003; Ley & Thomas, 2003; Palucki et al., 1997). Williamson reaction is a useful method to prepare ether compounds. In the case of the reaction between phenol and alkyl halide, phenols readily react with a mild base like potasuim carbonate to form phenoxide ions, which then substitute the –X group in the alkyl halide, forming an ether with an aryl group attached to it. In our ongoing project to synthesize novel ether compounds which can be used for biological research, we report herein the synthesis and crystal structure of the title compound, (I).

In the asymmetric unit of (I) in Fig. 1, the naphthalene ring is planar, with a maximum deviation of 0.0184 (18) Å for atom C1. The dihedral angle between the phenyl and naphthalene rings is 43.79 (7)°. The benzyloxy group (O1/C11–C17) is (-)anti-periplanar (-ap) and attached to the C1–C4/C9–C10 ring with C1—O1—C11—C12 torsion angle of -170.20 (14)°. Atoms O3, O4, C19 and C20 lie on the one plane whereas atoms O2, C8, C18 and C19 lie on the another plane. The dihedral angle between these two planes is 73.14 (12)°. The dihedral angle between the mean plane through the O3/O4/C19/C20 plane and naphthalene ring is 83.70 (9)°. The conformation of the oxyacetate unit is (-)anti-clinal (-ac) with C8—C18—C19—O4 torsion angle of -108.69 (16)°. A weak C10—H10A···O2 interaction generates a S(6) ring motif (Bernstein et al., 1995). Bond distances and angles have normal values (Allen et al., 1987).

The crystal packing of (I) in Fig. 2, shows that the molecules are stacked into column along the a axis and the adjacent columns were linked by weak C—H···O interactions. The crystal is stabilized by C—H···π interactions (Table 1); Cg₁, Cg₂ and Cg₃ are the centroids of C1–C4/C9–C10, C4–C9 and C12–C17 rings, respectively.

Related literature top

For related literature on hydrogen-bond motifs, see: Bernstein et al. (1995). For values of bond lengths, see: Allen et al. (1987). For related literature on bioactivities of compounds containing aromatic rings, see, for example: Hartwig (1998); Knepper et al. (2004); Kunz et al. (2003); Ley & Thomas (2003); Palucki et al. (1997). Cg1, Cg2 and Cg3 are the centroids of the C1–C4/C9–C10, C4–C9 and C12–C17 rings, respectively.

Experimental top

The title compound was synthesized by stirring a mixture of methyl 2-(2-hydroxynaphthalen-8-yl)-2-oxoacetate (1.0 g, 4.3 mmol), 3-A° molecular sieves (2.0 g), potassium carbonate (0.7 g, 5.1 mmol) and benzyl bromide (0.75 g, 4.4 mmol) in dry DMF (35 ml) for 24 h, after which it was filtered and the filtrate evaporated. The residue was recrystallized from ether–n-hexane mixture (2:1 v/v) to give the desired compound (I) (1.10 g, 80% yield). Single crystals suitable for X-ray diffraction analysis were obtained by slow evaporation of the solvent from an ether–n-hexane solution (m.p. 358 K).

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: APEX2 (Bruker, 2005); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2003).

Figures top

	Fig. 1. The asymmetric unit of (I), showing 50% probability displacement ellipsoids and the atomic numbering. The weak C—H···O intramolecular interaction is shown as a dashed line.
	Fig. 2. The crystal packing of (I), viewed down the c axis. Hydrogen bonds are shown as dashed lines.

Methyl 2-(7-benzyloxy-1-naphthyl)-2-oxoacetate top

Crystal data top

C₂₀H₁₆O₄	D_x = 1.385 Mg m⁻³
M_r = 320.33	Melting point: 358 K
Orthorhombic, P2₁2₁2₁	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2ab	Cell parameters from 2575 reflections
a = 5.6145 (3) Å	θ = 1.8–30.0°
b = 15.7422 (8) Å	µ = 0.10 mm⁻¹
c = 17.3843 (8) Å	T = 100 K
V = 1536.50 (13) Å³	Plate, colourless
Z = 4	0.58 × 0.32 × 0.10 mm
F(000) = 672

Data collection top

Bruker SMART APEXII CCD area-detector diffractometer	2575 independent reflections
Radiation source: fine-focus sealed tube	2380 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.039
Detector resolution: 8.33 pixels mm^-1	θ_max = 30.0°, θ_min = 1.8°
ω scans	h = −7→7
Absorption correction: multi-scan (SADABS; Bruker, 2005)	k = −22→22
T_min = 0.946, T_max = 0.991	l = −22→24
17379 measured reflections

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)] = 0.034	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.100	H-atom parameters constrained
S = 1.08	w = 1/[σ²(F_o²) + (0.0565P)² + 0.2831P] where P = (F_o² + 2F_c²)/3
2575 reflections	(Δ/σ)_max = 0.001
218 parameters	Δρ_max = 0.29 e Å⁻³
0 restraints	Δρ_min = −0.17 e Å⁻³

Crystal data top

C₂₀H₁₆O₄	V = 1536.50 (13) Å³
M_r = 320.33	Z = 4
Orthorhombic, P2₁2₁2₁	Mo Kα radiation
a = 5.6145 (3) Å	µ = 0.10 mm⁻¹
b = 15.7422 (8) Å	T = 100 K
c = 17.3843 (8) Å	0.58 × 0.32 × 0.10 mm

Data collection top

Bruker SMART APEXII CCD area-detector diffractometer	2575 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2005)	2380 reflections with I > 2σ(I)
T_min = 0.946, T_max = 0.991	R_int = 0.039
17379 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.034	0 restraints
wR(F²) = 0.100	H-atom parameters constrained
S = 1.08	Δρ_max = 0.29 e Å⁻³
2575 reflections	Δρ_min = −0.17 e Å⁻³
218 parameters

Special details top

Experimental. The low-temparture data was collected with the Oxford Cryosystem Cobra low-temperature attachment.

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
O1	0.3014 (2)	0.54915 (8)	0.63643 (7)	0.0236 (3)
O2	0.8876 (3)	0.51454 (8)	0.43322 (7)	0.0253 (3)
O3	1.0904 (3)	0.35791 (8)	0.33767 (8)	0.0268 (3)
O4	1.3439 (2)	0.46196 (8)	0.37431 (7)	0.0222 (3)
C1	0.4708 (3)	0.48752 (10)	0.63241 (10)	0.0189 (3)
C2	0.4861 (4)	0.43676 (10)	0.69963 (10)	0.0223 (3)
H2A	0.3821	0.4459	0.7404	0.027*
C3	0.6541 (3)	0.37447 (10)	0.70417 (10)	0.0213 (3)
H3A	0.6623	0.3409	0.7481	0.026*
C4	0.8161 (3)	0.35991 (10)	0.64334 (9)	0.0187 (3)
C5	0.9937 (4)	0.29689 (10)	0.64975 (10)	0.0218 (3)
H5A	1.0026	0.2646	0.6944	0.026*
C6	1.1535 (3)	0.28219 (10)	0.59170 (10)	0.0226 (4)
H6A	1.2696	0.2405	0.5970	0.027*
C7	1.1400 (3)	0.33079 (10)	0.52406 (10)	0.0209 (3)
H7A	1.2462	0.3199	0.4842	0.025*
C8	0.9712 (3)	0.39479 (10)	0.51538 (9)	0.0182 (3)
C9	0.8007 (3)	0.41091 (10)	0.57529 (9)	0.0171 (3)
C10	0.6209 (3)	0.47439 (9)	0.57108 (9)	0.0177 (3)
H10A	0.6048	0.5070	0.5268	0.021*
C11	0.2839 (3)	0.60828 (10)	0.57358 (9)	0.0192 (3)
H11A	0.2236	0.5798	0.5281	0.023*
H11B	0.4396	0.6316	0.5618	0.023*
C12	0.1165 (3)	0.67811 (10)	0.59753 (9)	0.0183 (3)
C13	0.1697 (3)	0.76264 (10)	0.57956 (10)	0.0202 (3)
H13A	0.3105	0.7757	0.5540	0.024*
C14	0.0126 (3)	0.82699 (10)	0.59983 (10)	0.0212 (3)
H14A	0.0485	0.8830	0.5875	0.025*
C15	−0.1971 (3)	0.80841 (10)	0.63826 (10)	0.0219 (3)
H15A	−0.3026	0.8517	0.6510	0.026*
C16	−0.2495 (3)	0.72467 (11)	0.65769 (10)	0.0219 (3)
H16A	−0.3884	0.7120	0.6845	0.026*
C17	−0.0931 (3)	0.66001 (10)	0.63687 (10)	0.0198 (3)
H17A	−0.1293	0.6040	0.6494	0.024*
C18	0.9888 (3)	0.44716 (10)	0.44555 (10)	0.0187 (3)
C19	1.1476 (3)	0.41483 (10)	0.38003 (9)	0.0189 (3)
C20	1.4989 (4)	0.44233 (11)	0.30990 (10)	0.0232 (3)
H20A	1.6051	0.4891	0.3010	0.035*
H20B	1.4044	0.4326	0.2647	0.035*
H20C	1.5899	0.3923	0.3214	0.035*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0271 (7)	0.0212 (5)	0.0224 (6)	0.0087 (5)	0.0058 (5)	0.0049 (5)
O2	0.0272 (7)	0.0212 (5)	0.0274 (6)	0.0057 (5)	0.0047 (6)	0.0037 (5)
O3	0.0274 (7)	0.0242 (6)	0.0287 (6)	−0.0045 (6)	0.0028 (6)	−0.0071 (5)
O4	0.0216 (6)	0.0225 (5)	0.0224 (6)	−0.0041 (5)	0.0035 (5)	−0.0030 (5)
C1	0.0202 (8)	0.0157 (6)	0.0207 (7)	0.0022 (6)	0.0002 (7)	0.0000 (6)
C2	0.0264 (9)	0.0206 (7)	0.0198 (7)	0.0030 (7)	0.0034 (7)	0.0013 (6)
C3	0.0265 (9)	0.0190 (7)	0.0185 (7)	0.0011 (7)	−0.0011 (7)	0.0026 (6)
C4	0.0216 (8)	0.0146 (6)	0.0198 (7)	−0.0004 (6)	−0.0027 (7)	−0.0008 (6)
C5	0.0270 (9)	0.0175 (7)	0.0210 (8)	0.0019 (7)	−0.0059 (7)	0.0012 (6)
C6	0.0238 (9)	0.0171 (7)	0.0268 (8)	0.0036 (6)	−0.0041 (7)	−0.0003 (6)
C7	0.0201 (8)	0.0192 (7)	0.0233 (8)	0.0015 (7)	−0.0001 (7)	−0.0027 (6)
C8	0.0189 (8)	0.0159 (6)	0.0199 (7)	−0.0004 (6)	−0.0004 (6)	−0.0014 (6)
C9	0.0188 (7)	0.0142 (6)	0.0183 (7)	−0.0013 (6)	−0.0013 (6)	−0.0020 (5)
C10	0.0196 (8)	0.0158 (7)	0.0177 (7)	0.0006 (6)	−0.0014 (6)	0.0006 (6)
C11	0.0218 (8)	0.0184 (7)	0.0175 (7)	0.0026 (6)	0.0002 (6)	0.0015 (6)
C12	0.0189 (8)	0.0187 (7)	0.0174 (7)	0.0017 (6)	−0.0029 (6)	−0.0014 (6)
C13	0.0218 (8)	0.0197 (7)	0.0192 (7)	−0.0006 (6)	−0.0003 (7)	0.0018 (6)
C14	0.0268 (9)	0.0156 (7)	0.0210 (7)	−0.0003 (7)	−0.0033 (7)	−0.0001 (6)
C15	0.0244 (9)	0.0202 (7)	0.0211 (8)	0.0046 (7)	−0.0018 (7)	−0.0032 (6)
C16	0.0193 (8)	0.0248 (8)	0.0216 (8)	0.0010 (7)	−0.0004 (7)	−0.0011 (6)
C17	0.0194 (8)	0.0177 (6)	0.0224 (8)	−0.0003 (6)	−0.0020 (7)	0.0009 (6)
C18	0.0183 (7)	0.0177 (7)	0.0201 (7)	−0.0021 (6)	0.0007 (6)	−0.0021 (6)
C19	0.0185 (8)	0.0167 (6)	0.0214 (7)	0.0007 (6)	0.0000 (6)	0.0012 (6)
C20	0.0202 (8)	0.0262 (8)	0.0232 (8)	−0.0001 (7)	0.0046 (7)	0.0009 (6)

Geometric parameters (Å, º) top

O1—C1	1.361 (2)	C8—C18	1.471 (2)
O1—C11	1.4387 (19)	C9—C10	1.422 (2)
O2—C18	1.222 (2)	C10—H10A	0.9300
O3—C19	1.204 (2)	C11—C12	1.505 (2)
O4—C19	1.332 (2)	C11—H11A	0.9700
O4—C20	1.452 (2)	C11—H11B	0.9700
C1—C10	1.375 (2)	C12—C17	1.391 (2)
C1—C2	1.418 (2)	C12—C13	1.399 (2)
C2—C3	1.363 (2)	C13—C14	1.389 (2)
C2—H2A	0.9300	C13—H13A	0.9300
C3—C4	1.414 (2)	C14—C15	1.385 (3)
C3—H3A	0.9300	C14—H14A	0.9300
C4—C5	1.411 (2)	C15—C16	1.392 (2)
C4—C9	1.432 (2)	C15—H15A	0.9300
C5—C6	1.370 (3)	C16—C17	1.392 (2)
C5—H5A	0.9300	C16—H16A	0.9300
C6—C7	1.405 (2)	C17—H17A	0.9300
C6—H6A	0.9300	C18—C19	1.534 (2)
C7—C8	1.391 (2)	C20—H20A	0.9600
C7—H7A	0.9300	C20—H20B	0.9600
C8—C9	1.437 (2)	C20—H20C	0.9600

C1—O1—C11	118.03 (13)	C12—C11—H11A	110.2
C19—O4—C20	115.80 (13)	O1—C11—H11B	110.2
O1—C1—C10	125.14 (14)	C12—C11—H11B	110.2
O1—C1—C2	113.69 (15)	H11A—C11—H11B	108.5
C10—C1—C2	121.15 (15)	C17—C12—C13	119.04 (16)
C3—C2—C1	119.68 (16)	C17—C12—C11	120.99 (15)
C3—C2—H2A	120.2	C13—C12—C11	119.97 (16)
C1—C2—H2A	120.2	C14—C13—C12	120.11 (17)
C2—C3—C4	121.24 (15)	C14—C13—H13A	119.9
C2—C3—H3A	119.4	C12—C13—H13A	119.9
C4—C3—H3A	119.4	C15—C14—C13	120.55 (15)
C5—C4—C3	120.65 (15)	C15—C14—H14A	119.7
C5—C4—C9	120.12 (16)	C13—C14—H14A	119.7
C3—C4—C9	119.22 (14)	C14—C15—C16	119.77 (16)
C6—C5—C4	121.56 (15)	C14—C15—H15A	120.1
C6—C5—H5A	119.2	C16—C15—H15A	120.1
C4—C5—H5A	119.2	C17—C16—C15	119.75 (17)
C5—C6—C7	119.30 (16)	C17—C16—H16A	120.1
C5—C6—H6A	120.4	C15—C16—H16A	120.1
C7—C6—H6A	120.4	C12—C17—C16	120.77 (15)
C8—C7—C6	121.45 (17)	C12—C17—H17A	119.6
C8—C7—H7A	119.3	C16—C17—H17A	119.6
C6—C7—H7A	119.3	O2—C18—C8	126.88 (16)
C7—C8—C9	120.19 (15)	O2—C18—C19	115.34 (15)
C7—C8—C18	116.73 (15)	C8—C18—C19	117.78 (14)
C9—C8—C18	122.94 (15)	O3—C19—O4	126.16 (16)
C10—C9—C4	118.63 (15)	O3—C19—C18	123.10 (16)
C10—C9—C8	124.02 (14)	O4—C19—C18	110.59 (14)
C4—C9—C8	117.35 (14)	O4—C20—H20A	109.5
C1—C10—C9	120.05 (14)	O4—C20—H20B	109.5
C1—C10—H10A	120.0	H20A—C20—H20B	109.5
C9—C10—H10A	120.0	O4—C20—H20C	109.5
O1—C11—C12	107.76 (13)	H20A—C20—H20C	109.5
O1—C11—H11A	110.2	H20B—C20—H20C	109.5

C11—O1—C1—C10	−3.3 (2)	C4—C9—C10—C1	1.9 (2)
C11—O1—C1—C2	175.28 (15)	C8—C9—C10—C1	−177.56 (15)
O1—C1—C2—C3	−177.83 (16)	C1—O1—C11—C12	−170.20 (14)
C10—C1—C2—C3	0.8 (3)	O1—C11—C12—C17	−42.1 (2)
C1—C2—C3—C4	0.7 (3)	O1—C11—C12—C13	138.51 (16)
C2—C3—C4—C5	178.08 (17)	C17—C12—C13—C14	−1.0 (3)
C2—C3—C4—C9	−0.9 (3)	C11—C12—C13—C14	178.34 (15)
C3—C4—C5—C6	−179.53 (16)	C12—C13—C14—C15	0.3 (3)
C9—C4—C5—C6	−0.6 (3)	C13—C14—C15—C16	0.9 (3)
C4—C5—C6—C7	−0.2 (3)	C14—C15—C16—C17	−1.4 (3)
C5—C6—C7—C8	1.4 (3)	C13—C12—C17—C16	0.5 (3)
C6—C7—C8—C9	−1.9 (3)	C11—C12—C17—C16	−178.85 (16)
C6—C7—C8—C18	174.04 (15)	C15—C16—C17—C12	0.7 (3)
C5—C4—C9—C10	−179.41 (15)	C7—C8—C18—O2	−166.30 (17)
C3—C4—C9—C10	−0.4 (2)	C9—C8—C18—O2	9.5 (3)
C5—C4—C9—C8	0.1 (2)	C7—C8—C18—C19	14.4 (2)
C3—C4—C9—C8	179.09 (15)	C9—C8—C18—C19	−169.81 (15)
C7—C8—C9—C10	−179.42 (15)	C20—O4—C19—O3	0.8 (2)
C18—C8—C9—C10	4.9 (3)	C20—O4—C19—C18	−174.75 (13)
C7—C8—C9—C4	1.1 (2)	O2—C18—C19—O3	−103.8 (2)
C18—C8—C9—C4	−174.57 (15)	C8—C18—C19—O3	75.6 (2)
O1—C1—C10—C9	176.33 (15)	O2—C18—C19—O4	71.91 (19)
C2—C1—C10—C9	−2.1 (3)	C8—C18—C19—O4	−108.69 (16)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C10—H10A···O2	0.93	2.28	2.896 (2)	124
C14—H14A···O2ⁱ	0.93	2.52	3.315 (2)	144
C20—H20B···O1ⁱⁱ	0.96	2.53	3.458 (2)	163
C7—H7A···Cg2ⁱⁱⁱ	0.93	3.15	3.8529 (18)	134
C13—H13A···Cg3^iv	0.93	3.13	3.8070 (19)	132
C17—H17A···Cg1^v	0.93	3.12	4.0033 (17)	159

Symmetry codes: (i) x−1/2, −y+3/2, −z+1; (ii) −x+3/2, −y+1, z−1/2; (iii) −x, y+1/2, −z+3/2; (iv) −x, y+3/2, −z+3/2; (v) x−1, y, z.

Experimental details

Crystal data
Chemical formula	C₂₀H₁₆O₄
M_r	320.33
Crystal system, space group	Orthorhombic, P2₁2₁2₁
Temperature (K)	100
a, b, c (Å)	5.6145 (3), 15.7422 (8), 17.3843 (8)
V (Å³)	1536.50 (13)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.10
Crystal size (mm)	0.58 × 0.32 × 0.10

Data collection
Diffractometer	Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2005)
T_min, T_max	0.946, 0.991
No. of measured, independent and observed [I > 2σ(I)] reflections	17379, 2575, 2380
R_int	0.039
(sin θ/λ)_max (Å⁻¹)	0.703

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.034, 0.100, 1.08
No. of reflections	2575
No. of parameters	218
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.29, −0.17

Computer programs: APEX2 (Bruker, 2005), SAINT (Bruker, 2005), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2003).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C10—H10A···O2	0.93	2.2763	2.896 (2)	124
C14—H14A···O2ⁱ	0.93	2.5211	3.315 (2)	144
C20—H20B···O1ⁱⁱ	0.96	2.5278	3.458 (2)	163
C7—H7A···Cg2ⁱⁱⁱ	0.93	3.1463	3.8529 (18)	134
C13—H13A···Cg3^iv	0.93	3.1249	3.8070 (19)	132
C17—H17A···Cg1^v	0.93	3.1191	4.0033 (17)	159

Symmetry codes: (i) x−1/2, −y+3/2, −z+1; (ii) −x+3/2, −y+1, z−1/2; (iii) −x, y+1/2, −z+3/2; (iv) −x, y+3/2, −z+3/2; (v) x−1, y, z.

Footnotes

‡Additional correspondence author, e-mail: suchada.c@psu.ac.th.

§Current address: Department of Chemistry, Handan College, Handan, Hebei 056005, People's Republic of China.

Acknowledgements

The authors gratefully acknowledge the financial assistance of Beijing Normal University. The authors also thank the Universiti Sains Malaysia for a Research University Golden Goose grant (No. 1001/PFIZIK/811012).

References

Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–19. CrossRef Web of Science Google Scholar
Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555–1573. CrossRef CAS Web of Science Google Scholar
Bruker (2005). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Hartwig, J. F. (1998). Angew. Chem. Int. Ed. 37, 2046–2067. CrossRef CAS Google Scholar
Knepper, K., Lormann, M. E. P. & Brase, S. (2004). J. Comb. Chem. 6, 460–463. Web of Science CrossRef PubMed CAS Google Scholar
Kunz, K., Scholz, U. & Ganzer, D. (2003). Synlett, pp. 2428–2439. Web of Science CrossRef Google Scholar
Ley, S. V. & Thomas, A. W. (2003). Angew. Chem. Int. Ed. 42, 5400–5049. Web of Science CrossRef CAS Google Scholar
Palucki, M., Wolfe, J. P. & Buchwald, S. L. (1997). J. Am. Chem. Soc. 119, 3395–3396. CrossRef CAS Web of Science Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Spek, A. L. (2003). J. Appl. Cryst. 36, 7–13. Web of Science CrossRef CAS IUCr Journals Google Scholar