3-[(E)-1-(Benzyl­oxyimino)eth­yl]-2-oxo-2H-chromen-7-yl acetate

Wang, H.; Xu, S.; Zeng, Z.; Zhang, Y.

doi:10.1107/S1600536810003454

organic compounds

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ISSN: 2056-9890

Volume 66| Part 3| March 2010| Page o511

doi:10.1107/S1600536810003454

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3-[(E)-1-(Benzyloxyimino)ethyl]-2-oxo-2H-chromen-7-yl acetate

Hui Wang,^a ^* Su-hua Xu,^a Zhuo Zeng ^a and Yong-hong Zhang ^a

^aSchool of Chemistry and Environment, South China Normal University, Guangzhou 510006, People's Republic of China
^*Correspondence e-mail: Huiwang@scnu.edu.cn

(Received 19 January 2010; accepted 28 January 2010; online 3 February 2010)

The title compound, C₂₀H₁₇NO₅, was prepared by the reaction of 3-acetyl-2-oxo-2H-chromen-7-yl acetate with benzyloxyamine. The molecule adopts an E configuration with respect to the C=N double bond. The dihedral angles between the coumarin ring system, the phenyl ring and the C=N—O—C plane of the oxime unit are 35.83 (6), 35.8 (2) and 69.99 (15)°, respectively. In the crystal, a two-dimensional supramolecular network is assembled through weak intermolecular C—H⋯O hydrogen-bonding interactions.

Related literature

For the pharmacological applications of Schiff base compounds derived from coumarins, see: Jolanta et al. (2006 ); Kontogiorgis et al. (2006 ); Kontogiorgis & Hadjipavlou-Litina (2004 ); Nofal et al. (2000 ). For their use as dyes, fluorescent agents and as chemosensors, see: Kachkovski et al. (2004 ); Turki et al. (2006 ); Li et al. (2009 ).

Experimental

Crystal data

C₂₀H₁₇NO₅
M_r = 351.35
Triclinic, $[P \overline 1]$
a = 6.3901 (9) Å
b = 11.2413 (16) Å
c = 12.9298 (18) Å
α = 102.643 (2)°
β = 96.923 (2)°
γ = 101.860 (2)°
V = 873.5 (2) Å³
Z = 2
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 298 K
0.25 × 0.20 × 0.18 mm

Data collection

Bruker APEXII area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2004 ) T_min = 0.977, T_max = 0.983
5311 measured reflections
3792 independent reflections
2335 reflections with I > 2σ(I)
R_int = 0.025

Refinement

R[F² > 2σ(F²)] = 0.051
wR(F²) = 0.166
S = 1.09
3792 reflections
238 parameters
H-atom parameters constrained
Δρ_max = 0.33 e Å⁻³
Δρ_min = −0.23 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C6—H6⋯O5ⁱ	0.93	2.51	3.393 (3)	159
C18—H18⋯O5ⁱⁱ	0.93	2.67	3.552 (3)	160
C8—H8⋯O1ⁱⁱⁱ	0.93	2.65	3.397 (2)	138
Symmetry codes: (i) x+1, y, z; (ii) x+2, y+1, z+1; (iii) -x-1, -y+1, -z+1.

Data collection: APEX2 (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XP in SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810003454/sj2717sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536810003454/sj2717Isup2.hkl

checkCIF report

Comment top

Coumarin-derived Schiff bases have attracted much attention due to their potential pharmacological applications as antitumor (Jolanta et al., 2006), anti-inflammatory (Kontogiorgis & Hadjipavlou-Litina 2004), antibacterial (Nofal et al., 2000) and antifungal agents (Kontogiorgis et al., 2006). In addition, they can also be used as dyes (Kachkovski et al., 2004), fluorescent agents (Turki et al., 2006) and as colorimetric chemosensors (Li et al., 2009). In our study of bioactive compounds, a series of coumarin-derived Schiff bases have been synthesized. Herein, we report the crystal structure of the title compound, Fig. 1, obtained by the reaction of 3-acetyl-2-oxo-2H-chromen-7-yl acetate with benzyloxy-amine.

The title molecule is composed of a coumarin core with acetoxyl and benzyloxyiminoethyl substituents. The dihedral angles between the coumarin ring system, the phenyl ring and the C=N—O—C plane of the oxime unit are 35.83 (6)°, 35.8 (2) ° and 69.99 (15) °, respectively. The benzyloxyiminoethyl and coumarin systems are located on opposite sides of the C=N double bond plane, therefor the molecule presents an E configuration. In the crystal structure, intermolecular C6—H6···O5 hydrogen bonding interactions (Table 1) assemble a two-dimensional supramolecular layer as shown in Fig. 2. Additional weak C8—H8···O1 and C18—H18···O5 contacts are also observed. The overall crystal packing is shown in Fig. 3.

Related literature top

For the pharmacological applications of Schiff base compounds derived from coumarins, see: Jolanta et al. (2006); Kontogiorgis et al. (2006); Kontogiorgis & Hadjipavlou-Litina (2004); Nofal et al. (2000). For their use as dyes, fluorescent agents and as chemosensors, see: Kachkovski et al. (2004); Turki et al. (2006); Li et al. (2009).

Experimental top

A solution of benzyloxy-amine hydrochloride (2 mmol) in ethanol (10 ml) was added to a solution of 3-acetyl-2-oxo-2H-chromen-7-yl acetate (1 mmol) in ethanol (10 ml) at room temperature, the solution pH was then maintained at a value of 7 by the addition of sodium hydroxide. The reaction mixture was refluxed for 5 h at 353 K (monitored by TLC). After completion of the reaction, the reaction solution was purified by column chromatography (ethyl acetate: petroleum ether = 2:3). The eluate was evaporated to give the title compound (286 mg, yield: 81.5%). Single crystals suitable for X-ray analysis were obtained by recrystallization from DMSO, m.p. 426 K. ESI-MS (m/z): 352 (M+1); Analysis calculated for C₂₀H₁₇NO₅: C 68.37%, H 4.88%, N 3.99%; Found: C 68.54%, H 4.32%, N 3.78%.

Computing details top

Data collection: APEX2 (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT (Bruker, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XP in SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top

	Fig. 1. The molecular structure of the title compound showing the atom numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.
	Fig. 2. Part of the crystal structure of the title compound showing weak C—H···O hydrogen bonds as dashed lines.
	Fig. 3. Crystal packing in the title compound.

3-[(E)-1-(Benzyloxyimino)ethyl]-2-oxo-2H-chromen-7-yl acetate top

Crystal data top

C₂₀H₁₇NO₅	Z = 2
M_r = 351.35	F(000) = 368
Triclinic, P1	D_x = 1.336 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 6.3901 (9) Å	Cell parameters from 1332 reflections
b = 11.2413 (16) Å	θ = 2.8–24.5°
c = 12.9298 (18) Å	µ = 0.10 mm⁻¹
α = 102.643 (2)°	T = 298 K
β = 96.923 (2)°	Block, colorless
γ = 101.860 (2)°	0.25 × 0.20 × 0.18 mm
V = 873.5 (2) Å³

Data collection top

Bruker APEXII area-detector diffractometer	3792 independent reflections
Radiation source: fine-focus sealed tube	2335 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.025
ϕ and ω scans	θ_max = 27.3°, θ_min = 2.2°
Absorption correction: multi-scan (SADABS; Bruker, 2004)	h = −8→6
T_min = 0.977, T_max = 0.983	k = −12→14
5311 measured reflections	l = −16→16

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)] = 0.051	H-atom parameters constrained
wR(F²) = 0.166	w = 1/[σ²(F_o²) + (0.076P)² + 0.0611P] where P = (F_o² + 2F_c²)/3
S = 1.09	(Δ/σ)_max < 0.001
3792 reflections	Δρ_max = 0.33 e Å⁻³
238 parameters	Δρ_min = −0.23 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: 0.010 (4)

Crystal data top

C₂₀H₁₇NO₅	γ = 101.860 (2)°
M_r = 351.35	V = 873.5 (2) Å³
Triclinic, P1	Z = 2
a = 6.3901 (9) Å	Mo Kα radiation
b = 11.2413 (16) Å	µ = 0.10 mm⁻¹
c = 12.9298 (18) Å	T = 298 K
α = 102.643 (2)°	0.25 × 0.20 × 0.18 mm
β = 96.923 (2)°

Data collection top

Bruker APEXII area-detector diffractometer	3792 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2004)	2335 reflections with I > 2σ(I)
T_min = 0.977, T_max = 0.983	R_int = 0.025
5311 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.051	0 restraints
wR(F²) = 0.166	H-atom parameters constrained
S = 1.09	Δρ_max = 0.33 e Å⁻³
3792 reflections	Δρ_min = −0.23 e Å⁻³
238 parameters

Special details top

Experimental. FT—IR (KBr): 1763, 1717, 1615, 1426, 1365, 1200, 1030 cm^-1; ¹H NMR δ (400 Hz, DMSO, TMS): 8.08 (s, 1H), 7.83 (d, J = 8.4 Hz, 1H), 7.36–7.28 (m, 5H) 7.26 (d, J = 2.0 Hz, 1H), 7.14 (dd, J = 2.0, 8.4 Hz, 1H), 5.17 (s, 2H), 2.27 (s, 3H), 2.11 (s, 3H).

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	−0.33761 (19)	0.48915 (12)	0.62680 (10)	0.0488 (4)
C2	−0.2517 (3)	0.56481 (18)	0.72817 (15)	0.0499 (5)
O2	−0.3700 (2)	0.62098 (15)	0.77276 (12)	0.0710 (5)
C3	−0.0274 (3)	0.56859 (17)	0.77165 (15)	0.0472 (5)
C4	0.0814 (3)	0.49479 (17)	0.71383 (15)	0.0478 (5)
H4	0.2234	0.4970	0.7421	0.057*
C5	0.0893 (3)	0.33485 (18)	0.54693 (16)	0.0504 (5)
H5	0.2301	0.3320	0.5725	0.060*
C6	−0.0133 (3)	0.26229 (17)	0.44758 (16)	0.0503 (5)
H6	0.0568	0.2097	0.4062	0.060*
C7	−0.2229 (3)	0.26729 (17)	0.40849 (15)	0.0448 (4)
O4	−0.3080 (2)	0.19654 (12)	0.30368 (10)	0.0542 (4)
C20	−0.5180 (4)	0.12835 (19)	0.27716 (18)	0.0591 (6)
O5	−0.6377 (3)	0.12328 (15)	0.34060 (14)	0.0791 (5)
C21	−0.5679 (4)	0.0639 (2)	0.1608 (2)	0.0821 (8)
H21C	−0.7167	0.0173	0.1424	0.123*
H21A	−0.4749	0.0076	0.1455	0.123*
H21B	−0.5445	0.1251	0.1194	0.123*
C8	−0.3309 (3)	0.34359 (17)	0.46779 (14)	0.0450 (4)
H8	−0.4706	0.3471	0.4410	0.054*
C9	−0.2257 (3)	0.41476 (16)	0.56822 (14)	0.0415 (4)
C10	−0.0149 (3)	0.41373 (16)	0.61081 (14)	0.0427 (4)
C11	0.0738 (3)	0.65509 (19)	0.87771 (16)	0.0539 (5)
C12	0.0328 (4)	0.7832 (2)	0.90913 (19)	0.0729 (7)
H12C	0.1607	0.8404	0.9536	0.109*
H12B	−0.0857	0.7804	0.9484	0.109*
H12A	−0.0030	0.8111	0.8456	0.109*
N1	0.2041 (3)	0.61121 (16)	0.93402 (13)	0.0644 (5)
O3	0.3083 (3)	0.70165 (14)	1.03000 (11)	0.0744 (5)
C13	0.4579 (5)	0.6475 (3)	1.0870 (2)	0.0940 (9)
H13B	0.5690	0.6295	1.0452	0.113*
H13A	0.3816	0.5700	1.1006	0.113*
C14	0.5568 (4)	0.74251 (19)	1.19015 (17)	0.0609 (6)
C15	0.4399 (4)	0.7731 (2)	1.26843 (19)	0.0677 (6)
H15	0.2937	0.7326	1.2573	0.081*
C16	0.5268 (5)	0.8596 (2)	1.3618 (2)	0.0812 (8)
H16	0.4415	0.8772	1.4139	0.097*
C17	0.7365 (5)	0.9205 (2)	1.3795 (2)	0.0820 (8)
H17	0.7944	0.9811	1.4437	0.098*
C18	0.8661 (4)	0.8957 (3)	1.3058 (2)	0.0842 (8)
H18	1.0115	0.9384	1.3194	0.101*
C19	0.7778 (4)	0.8050 (3)	1.2092 (2)	0.0817 (7)
H19	0.8644	0.7862	1.1579	0.098*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0384 (7)	0.0550 (8)	0.0484 (8)	0.0149 (6)	0.0013 (6)	0.0035 (6)
C2	0.0446 (11)	0.0558 (11)	0.0473 (11)	0.0116 (9)	0.0061 (9)	0.0102 (9)
O2	0.0508 (9)	0.0869 (11)	0.0646 (10)	0.0236 (8)	0.0070 (7)	−0.0079 (8)
C3	0.0426 (10)	0.0514 (11)	0.0448 (10)	0.0066 (8)	0.0044 (8)	0.0123 (8)
C4	0.0359 (10)	0.0543 (11)	0.0510 (11)	0.0074 (8)	0.0004 (8)	0.0153 (9)
C5	0.0354 (10)	0.0531 (11)	0.0627 (12)	0.0126 (8)	0.0064 (9)	0.0138 (9)
C6	0.0430 (11)	0.0463 (10)	0.0618 (12)	0.0125 (8)	0.0130 (9)	0.0103 (9)
C7	0.0427 (10)	0.0419 (9)	0.0480 (11)	0.0059 (8)	0.0076 (8)	0.0118 (8)
O4	0.0472 (8)	0.0580 (8)	0.0494 (8)	0.0078 (6)	0.0067 (6)	0.0023 (6)
C20	0.0505 (13)	0.0480 (11)	0.0688 (14)	0.0118 (9)	0.0011 (11)	−0.0009 (10)
O5	0.0550 (10)	0.0705 (10)	0.0932 (12)	−0.0003 (8)	0.0205 (9)	−0.0079 (9)
C21	0.0753 (16)	0.0762 (16)	0.0731 (16)	0.0155 (13)	−0.0072 (13)	−0.0128 (13)
C8	0.0374 (10)	0.0488 (10)	0.0481 (11)	0.0125 (8)	0.0029 (8)	0.0109 (8)
C9	0.0377 (10)	0.0428 (9)	0.0464 (10)	0.0126 (7)	0.0081 (8)	0.0128 (8)
C10	0.0364 (10)	0.0432 (9)	0.0472 (10)	0.0058 (7)	0.0054 (8)	0.0134 (8)
C11	0.0495 (12)	0.0610 (12)	0.0456 (11)	0.0079 (9)	0.0042 (9)	0.0091 (9)
C12	0.0735 (16)	0.0703 (15)	0.0628 (14)	0.0169 (12)	0.0027 (12)	−0.0030 (11)
N1	0.0720 (12)	0.0609 (11)	0.0453 (10)	0.0069 (9)	−0.0095 (9)	0.0015 (8)
O3	0.0890 (12)	0.0662 (10)	0.0523 (9)	0.0159 (8)	−0.0181 (8)	0.0014 (7)
C13	0.126 (2)	0.0769 (17)	0.0661 (16)	0.0340 (16)	−0.0280 (15)	0.0053 (13)
C14	0.0722 (15)	0.0542 (12)	0.0487 (12)	0.0134 (11)	−0.0092 (11)	0.0092 (9)
C15	0.0686 (15)	0.0641 (14)	0.0688 (15)	0.0136 (11)	0.0064 (12)	0.0186 (12)
C16	0.109 (2)	0.0721 (16)	0.0676 (16)	0.0310 (16)	0.0149 (15)	0.0201 (13)
C17	0.099 (2)	0.0624 (15)	0.0700 (17)	0.0142 (15)	−0.0147 (16)	0.0070 (13)
C18	0.0612 (16)	0.0781 (17)	0.098 (2)	−0.0013 (13)	−0.0165 (15)	0.0231 (15)
C19	0.0776 (18)	0.0987 (19)	0.0770 (17)	0.0287 (15)	0.0165 (14)	0.0307 (15)

Geometric parameters (Å, º) top

O1—C9	1.372 (2)	C9—C10	1.396 (2)
O1—C2	1.375 (2)	C11—N1	1.283 (3)
C2—O2	1.202 (2)	C11—C12	1.494 (3)
C2—C3	1.464 (3)	C12—H12C	0.9600
C3—C4	1.350 (3)	C12—H12B	0.9600
C3—C11	1.479 (3)	C12—H12A	0.9600
C4—C10	1.423 (2)	N1—O3	1.410 (2)
C4—H4	0.9300	O3—C13	1.447 (3)
C5—C6	1.365 (3)	C13—C14	1.489 (3)
C5—C10	1.403 (3)	C13—H13B	0.9700
C5—H5	0.9300	C13—H13A	0.9700
C6—C7	1.390 (3)	C14—C15	1.355 (3)
C6—H6	0.9300	C14—C19	1.408 (3)
C7—C8	1.372 (3)	C15—C16	1.347 (3)
C7—O4	1.392 (2)	C15—H15	0.9300
O4—C20	1.363 (2)	C16—C17	1.340 (4)
C20—O5	1.190 (2)	C16—H16	0.9300
C20—C21	1.483 (3)	C17—C18	1.356 (4)
C21—H21C	0.9600	C17—H17	0.9300
C21—H21A	0.9600	C18—C19	1.398 (4)
C21—H21B	0.9600	C18—H18	0.9300
C8—C9	1.375 (2)	C19—H19	0.9300
C8—H8	0.9300

C9—O1—C2	122.88 (14)	C5—C10—C4	124.61 (17)
O2—C2—O1	116.29 (17)	N1—C11—C3	113.44 (18)
O2—C2—C3	126.37 (18)	N1—C11—C12	125.35 (19)
O1—C2—C3	117.34 (17)	C3—C11—C12	121.10 (18)
C4—C3—C2	119.42 (17)	C11—C12—H12C	109.5
C4—C3—C11	122.05 (18)	C11—C12—H12B	109.5
C2—C3—C11	118.53 (17)	H12C—C12—H12B	109.5
C3—C4—C10	121.90 (17)	C11—C12—H12A	109.5
C3—C4—H4	119.0	H12C—C12—H12A	109.5
C10—C4—H4	119.0	H12B—C12—H12A	109.5
C6—C5—C10	120.80 (17)	C11—N1—O3	110.70 (17)
C6—C5—H5	119.6	N1—O3—C13	107.54 (16)
C10—C5—H5	119.6	O3—C13—C14	106.20 (19)
C5—C6—C7	119.80 (18)	O3—C13—H13B	110.5
C5—C6—H6	120.1	C14—C13—H13B	110.5
C7—C6—H6	120.1	O3—C13—H13A	110.5
C8—C7—C6	121.47 (17)	C14—C13—H13A	110.5
C8—C7—O4	122.92 (16)	H13B—C13—H13A	108.7
C6—C7—O4	115.48 (16)	C15—C14—C19	117.5 (2)
C20—O4—C7	120.76 (15)	C15—C14—C13	122.1 (2)
O5—C20—O4	123.2 (2)	C19—C14—C13	120.4 (2)
O5—C20—C21	127.0 (2)	C16—C15—C14	122.7 (2)
O4—C20—C21	109.8 (2)	C16—C15—H15	118.7
C20—C21—H21C	109.5	C14—C15—H15	118.7
C20—C21—H21A	109.5	C17—C16—C15	119.9 (3)
H21C—C21—H21A	109.5	C17—C16—H16	120.0
C20—C21—H21B	109.5	C15—C16—H16	120.0
H21C—C21—H21B	109.5	C16—C17—C18	121.5 (3)
H21A—C21—H21B	109.5	C16—C17—H17	119.3
C7—C8—C9	117.84 (17)	C18—C17—H17	119.3
C7—C8—H8	121.1	C17—C18—C19	119.0 (3)
C9—C8—H8	121.1	C17—C18—H18	120.5
O1—C9—C8	116.92 (15)	C19—C18—H18	120.5
O1—C9—C10	120.20 (16)	C18—C19—C14	119.4 (2)
C8—C9—C10	122.89 (16)	C18—C19—H19	120.3
C9—C10—C5	117.19 (17)	C14—C19—H19	120.3
C9—C10—C4	118.17 (16)

C9—O1—C2—O2	−176.76 (17)	C8—C9—C10—C4	177.57 (16)
C9—O1—C2—C3	2.8 (3)	C6—C5—C10—C9	−0.2 (3)
O2—C2—C3—C4	176.5 (2)	C6—C5—C10—C4	−178.29 (17)
O1—C2—C3—C4	−3.0 (3)	C3—C4—C10—C9	2.0 (3)
O2—C2—C3—C11	−4.3 (3)	C3—C4—C10—C5	−179.96 (18)
O1—C2—C3—C11	176.28 (16)	C4—C3—C11—N1	−36.2 (3)
C2—C3—C4—C10	0.6 (3)	C2—C3—C11—N1	144.62 (19)
C11—C3—C4—C10	−178.60 (16)	C4—C3—C11—C12	140.3 (2)
C10—C5—C6—C7	0.7 (3)	C2—C3—C11—C12	−38.9 (3)
C5—C6—C7—C8	−0.3 (3)	C3—C11—N1—O3	175.21 (16)
C5—C6—C7—O4	175.76 (16)	C12—C11—N1—O3	−1.1 (3)
C8—C7—O4—C20	−45.7 (2)	C11—N1—O3—C13	−177.84 (19)
C6—C7—O4—C20	138.31 (18)	N1—O3—C13—C14	−177.2 (2)
C7—O4—C20—O5	−1.4 (3)	O3—C13—C14—C15	67.9 (3)
C7—O4—C20—C21	179.04 (17)	O3—C13—C14—C19	−111.6 (3)
C6—C7—C8—C9	−0.6 (3)	C19—C14—C15—C16	0.1 (3)
O4—C7—C8—C9	−176.27 (15)	C13—C14—C15—C16	−179.4 (2)
C2—O1—C9—C8	179.99 (16)	C14—C15—C16—C17	0.8 (4)
C2—O1—C9—C10	−0.1 (3)	C15—C16—C17—C18	−1.0 (4)
C7—C8—C9—O1	−179.15 (15)	C16—C17—C18—C19	0.4 (4)
C7—C8—C9—C10	1.0 (3)	C17—C18—C19—C14	0.6 (4)
O1—C9—C10—C5	179.54 (15)	C15—C14—C19—C18	−0.8 (3)
C8—C9—C10—C5	−0.6 (3)	C13—C14—C19—C18	178.8 (2)
O1—C9—C10—C4	−2.3 (2)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C6—H6···O5ⁱ	0.93	2.51	3.393 (3)	159
C18—H18···O5ⁱⁱ	0.93	2.67	3.552 (3)	160
C8—H8···O1ⁱⁱⁱ	0.93	2.65	3.397 (2)	138

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

Experimental details

Crystal data
Chemical formula	C₂₀H₁₇NO₅
M_r	351.35
Crystal system, space group	Triclinic, P1
Temperature (K)	298
a, b, c (Å)	6.3901 (9), 11.2413 (16), 12.9298 (18)
α, β, γ (°)	102.643 (2), 96.923 (2), 101.860 (2)
V (Å³)	873.5 (2)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.10
Crystal size (mm)	0.25 × 0.20 × 0.18

Data collection
Diffractometer	Bruker APEXII area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2004)
T_min, T_max	0.977, 0.983
No. of measured, independent and observed [I > 2σ(I)] reflections	5311, 3792, 2335
R_int	0.025
(sin θ/λ)_max (Å⁻¹)	0.646

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.051, 0.166, 1.09
No. of reflections	3792
No. of parameters	238
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.33, −0.23

Computer programs: APEX2 (Bruker, 2004), SAINT (Bruker, 2004), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), XP in SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C6—H6···O5ⁱ	0.93	2.51	3.393 (3)	159.0
C18—H18···O5ⁱⁱ	0.93	2.67	3.552 (3)	159.6
C8—H8···O1ⁱⁱⁱ	0.93	2.65	3.397 (2)	137.6

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

Acknowledgements

We are grateful to the Science and Technology Plan Project of Guangdong Province (No. 2008B010600008) for financial support.

References

Bruker (2004). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Jolanta, N. M., Ewa, N. & Julita, G. (2006). Eur. J. Med. Chem. 41, 1301–1309. Web of Science PubMed Google Scholar
Kachkovski, O. D., Tolmachev, O. I., Kobryn, L. O., Bila, E. E. & Ganushchak, M. I. (2004). Dyes Pigments, 63, 203–211. CrossRef CAS Google Scholar
Kontogiorgis, C. A. & Hadjipavlou-Litina, D. J. (2004). Bioorg. Med. Chem. Lett. 14, 611–614. Web of Science CrossRef PubMed CAS Google Scholar
Kontogiorgis, C. A., Savvoglou, K. & Hadjipavlou-Litina, D. J. (2006). J. Enzyme Inhib. Med. Chem. 21, 21–29. Web of Science CrossRef PubMed CAS Google Scholar
Li, H. Y., Gao, S. & Xi, Z. (2009). Inorg. Chem. Commun. 12, 300–303. Web of Science CrossRef CAS Google Scholar
Nofal, Z. M., El-Zahar, M. I. & Abd El-Karim, S. S. (2000). Molecules, 5, 99–113. Web of Science CrossRef CAS Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Turki, H., Abid, S., El Gharbi, R. & Fery-Forgues, S. (2006). C. R. Chim. 9, 1252–1259. CrossRef CAS Google Scholar