1-[2-(3,4-Dichloro­phen­yl)-5-(3,4,5-trimethoxy­phen­yl)-2,3-dihydro-1,3,4-oxadiazol-3-yl]ethanone

He, D.-H.; Zhu, Y.-C.

doi:10.1107/S1600536808020771

1-[2-(3,4-Dichlorophenyl)-5-(3,4,5-trimethoxyphenyl)-2,3-dihydro-1,3,4-oxadiazol-3-yl]ethanone

The title compound, C₁₉H₁₈Cl₂N₂O₅, was synthesized by the reaction of N′-(3,4-dichlorobenzylidene)-3,4,5-trimethoxybenzohydrazide and acetic anhydride. The oxadiazole ring makes dihedral angles of 82.82 (7) and 9.92 (7)° with the 3,4-dichlorobenzene and the 3,4,5-trimethoxybenzene ring planes, respectively. The crystal structure is stabilized by intermolecular C—H

O and C—H

N hydrogen bonds. Intramolecular C—H

O and C—H

N hydrogen bonds are also present.

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Supporting information

	Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536808020771/wn2269sup1.cif Contains datablocks I, global
	Structure factor file (CIF format) https://doi.org/10.1107/S1600536808020771/wn2269Isup2.hkl Contains datablock I

CCDC reference: 700469

checkCIF report

Key indicators

Single-crystal X-ray study
T = 173 K
Mean (C-C) = 0.003 Å
R factor = 0.041
wR factor = 0.126
Data-to-parameter ratio = 16.2

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT029_ALERT_3_C _diffrn_measured_fraction_theta_full Low .......       0.97

Alert level G
PLAT793_ALERT_4_G Check the Absolute Configuration of C8     .....          S

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   1 ALERT level C = Check and explain
   1 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

Comment top

1,3,4-Oxadiazole derivatives are well known to possess a diverse range of bioactivities in the pharmaceutical and agrochemical fields; these include insecticidal, antibacterial, anticancer, and anti-inflammatory activities (Abdel et al., 2003; Abdel-Rahman & Farghaly, 2004; Chai et al., 2002; Mohd et al., 2004). Here we report the synthesis and crystal structure of a 1,3,4-oxadiazole derivative containing the 3,4,5-trimethoxyphenyl unit (Fig. 1).

The bond lengths and angles in the title compound are in good agreement with expected values. Though the C8 carbon of the oxadiazole ring is sp³ hybridized, the oxadiazole ring is essentially planar. The oxadiazole ring makes dihedral angles of 82.82 (7)° and 9.92 (7)° with the 3,4-dichlorobenzene and the 3,4,5-trimethoxybenzene ring planes, respectively. These angles are somewhat different from those in a similar crystal structure (Jin et al., 2006). The crystal structure exhibits intermolecular C—H··· O and C—H···N hydrogen bonds which stabilize the molecule. Intramolecular C—H···O and C—H···N hydrogen bonds are also present.

Related literature top

For related literature, see: Abdel et al. (2003); Abdel-Rahman & Farghaly (2004); Chai et al. (2002); Jin et al. (2006); Mohd et al. (2004).

Experimental top

N'-(3,4-Dichlorobenzylidene)-3,4,5-trimethoxybenzohydrazide (0.38 g, 1 mmol) in acetic anhydride (8 ml) was refluxed for 2 h until the starting material disappeared, as evidenced by TLC. The resulting cool mixture was then poured into cold water, after filtration. The residue was recrystallized by slow evaporation of a methanol solution.

Computing details top

Data collection: SMART (Bruker, 2001); cell refinement: SAINT-Plus (Bruker, 2003); data reduction: SAINT-Plus (Bruker, 2003); 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).

Figures top

Fig. 1. A view of the molecular structure of the title compound, showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level. Hydrogen atoms are represented by spheres of arbitrary radius.

1-[2-(3,4-Dichlorophenyl)-5-(3,4,5-trimethoxyphenyl)-2,3-dihydro-1,3,4- oxadiazol-3-yl]ethanone top

Crystal data top

C₁₉H₁₈Cl₂N₂O₅	F(000) = 880
M_r = 425.25	D_x = 1.465 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 5138 reflections
a = 7.6743 (4) Å	θ = 2.6–27.1°
b = 15.9516 (8) Å	µ = 0.37 mm⁻¹
c = 15.7483 (8) Å	T = 173 K
β = 90.894 (1)°	Block, colorless
V = 1927.63 (17) Å³	0.47 × 0.39 × 0.32 mm
Z = 4

Data collection top

Bruker SMART 1000 CCD diffractometer	4159 independent reflections
Radiation source: fine-focus sealed tube	3238 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.025
ω scans	θ_max = 27.2°, θ_min = 1.8°
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	h = −8→9
T_min = 0.845, T_max = 0.891	k = −20→18
10032 measured reflections	l = −13→20

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)] = 0.041	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.125	H-atom parameters constrained
S = 1.04	w = 1/[σ²(F_o²) + (0.0625P)² + 1.3473P] where P = (F_o² + 2F_c²)/3
4159 reflections	(Δ/σ)_max = 0.001
257 parameters	Δρ_max = 0.34 e Å⁻³
0 restraints	Δρ_min = −0.31 e Å⁻³

Crystal data top

C₁₉H₁₈Cl₂N₂O₅	V = 1927.63 (17) Å³
M_r = 425.25	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 7.6743 (4) Å	µ = 0.37 mm⁻¹
b = 15.9516 (8) Å	T = 173 K
c = 15.7483 (8) Å	0.47 × 0.39 × 0.32 mm
β = 90.894 (1)°

Data collection top

Bruker SMART 1000 CCD diffractometer	4159 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	3238 reflections with I > 2σ(I)
T_min = 0.845, T_max = 0.891	R_int = 0.025
10032 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.041	0 restraints
wR(F²) = 0.125	H-atom parameters constrained
S = 1.04	Δρ_max = 0.34 e Å⁻³
4159 reflections	Δρ_min = −0.31 e Å⁻³
257 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
Cl1	0.29475 (7)	0.36125 (4)	0.89108 (4)	0.04132 (18)
Cl2	0.44596 (8)	0.54237 (4)	0.85758 (4)	0.03835 (17)
C1	0.7817 (3)	0.05267 (12)	0.99579 (13)	0.0233 (4)
C2	0.7051 (3)	−0.00409 (13)	1.05104 (13)	0.0243 (4)
H2	0.6667	0.0136	1.1053	0.029*
C3	0.6857 (3)	−0.08687 (12)	1.02552 (13)	0.0254 (4)
C4	0.7416 (3)	−0.11303 (12)	0.94532 (13)	0.0250 (4)
C5	0.8160 (3)	−0.05492 (13)	0.89080 (12)	0.0239 (4)
C6	0.8351 (3)	0.02847 (12)	0.91572 (13)	0.0245 (4)
H6	0.8842	0.0683	0.8782	0.029*
C7	0.8153 (3)	0.13859 (12)	1.02448 (13)	0.0229 (4)
C8	0.9032 (3)	0.27301 (12)	1.00923 (13)	0.0240 (4)
H8	1.0284	0.2903	1.0080	0.029*
C9	0.7883 (3)	0.33955 (12)	0.97007 (12)	0.0231 (4)
C10	0.6145 (3)	0.32243 (12)	0.95089 (13)	0.0248 (4)
H10	0.5676	0.2685	0.9619	0.030*
C11	0.5100 (3)	0.38450 (13)	0.91558 (13)	0.0262 (4)
C12	0.5775 (3)	0.46408 (12)	0.90009 (13)	0.0263 (4)
C13	0.7498 (3)	0.48130 (13)	0.91895 (14)	0.0297 (5)
H13	0.7963	0.5354	0.9081	0.036*
C14	0.8548 (3)	0.41901 (13)	0.95392 (13)	0.0268 (4)
H14	0.9735	0.4308	0.9670	0.032*
C15	0.9181 (3)	0.29242 (13)	1.16484 (14)	0.0297 (5)
C16	0.8863 (4)	0.25497 (16)	1.25067 (15)	0.0428 (6)
H16A	0.9930	0.2277	1.2717	0.064*
H16B	0.7925	0.2134	1.2461	0.064*
H16C	0.8525	0.2993	1.2902	0.064*
C17	0.5778 (3)	−0.12792 (16)	1.16051 (15)	0.0383 (6)
H17A	0.6858	−0.1100	1.1892	0.058*
H17B	0.5312	−0.1774	1.1893	0.058*
H17C	0.4923	−0.0824	1.1623	0.058*
C18	0.6289 (3)	−0.22110 (15)	0.85465 (16)	0.0368 (5)
H18A	0.5145	−0.1941	0.8580	0.055*
H18B	0.6143	−0.2821	0.8544	0.055*
H18C	0.6861	−0.2036	0.8024	0.055*
C19	0.9654 (3)	−0.03053 (15)	0.76156 (14)	0.0351 (5)
H19A	0.8912	0.0169	0.7450	0.053*
H19B	1.0019	−0.0607	0.7106	0.053*
H19C	1.0685	−0.0098	0.7925	0.053*
N1	0.7969 (2)	0.16636 (10)	1.09988 (11)	0.0248 (4)
N2	0.8524 (2)	0.25043 (10)	1.09633 (10)	0.0251 (4)
O1	0.6131 (2)	−0.14829 (9)	1.07411 (10)	0.0345 (4)
O2	0.7344 (2)	−0.19688 (9)	0.92680 (10)	0.0354 (4)
O3	0.8701 (2)	−0.08591 (9)	0.81492 (9)	0.0304 (3)
O4	0.87792 (19)	0.19385 (8)	0.96599 (9)	0.0265 (3)
O5	0.9955 (2)	0.35859 (10)	1.15404 (11)	0.0401 (4)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cl1	0.0272 (3)	0.0402 (3)	0.0563 (4)	−0.0036 (2)	−0.0087 (2)	0.0089 (3)
Cl2	0.0433 (3)	0.0298 (3)	0.0419 (3)	0.0081 (2)	−0.0035 (2)	0.0093 (2)
C1	0.0220 (9)	0.0187 (9)	0.0290 (10)	0.0012 (8)	−0.0052 (8)	0.0011 (8)
C2	0.0229 (10)	0.0251 (10)	0.0249 (10)	0.0007 (8)	−0.0009 (8)	−0.0016 (8)
C3	0.0252 (10)	0.0206 (10)	0.0303 (11)	−0.0032 (8)	−0.0026 (8)	0.0056 (8)
C4	0.0283 (10)	0.0160 (9)	0.0307 (11)	0.0004 (8)	−0.0043 (8)	0.0000 (8)
C5	0.0243 (10)	0.0225 (10)	0.0247 (10)	0.0030 (8)	−0.0026 (8)	−0.0024 (7)
C6	0.0255 (10)	0.0217 (10)	0.0261 (10)	0.0000 (8)	−0.0034 (8)	0.0027 (8)
C7	0.0217 (9)	0.0210 (10)	0.0260 (10)	0.0009 (8)	−0.0011 (7)	0.0024 (7)
C8	0.0276 (10)	0.0172 (9)	0.0273 (10)	−0.0030 (8)	0.0015 (8)	−0.0023 (7)
C9	0.0280 (10)	0.0194 (9)	0.0219 (9)	0.0003 (8)	0.0017 (8)	−0.0018 (7)
C10	0.0277 (10)	0.0201 (10)	0.0266 (10)	−0.0032 (8)	0.0012 (8)	0.0004 (8)
C11	0.0243 (10)	0.0283 (11)	0.0261 (10)	−0.0029 (8)	0.0004 (8)	0.0007 (8)
C12	0.0328 (11)	0.0211 (10)	0.0250 (10)	0.0042 (8)	0.0020 (8)	0.0035 (8)
C13	0.0363 (12)	0.0201 (10)	0.0328 (11)	−0.0040 (9)	0.0030 (9)	0.0025 (8)
C14	0.0257 (10)	0.0216 (10)	0.0332 (11)	−0.0039 (8)	0.0016 (8)	−0.0016 (8)
C15	0.0363 (12)	0.0215 (10)	0.0312 (11)	0.0032 (9)	−0.0006 (9)	−0.0070 (8)
C16	0.0668 (17)	0.0339 (13)	0.0277 (12)	−0.0001 (12)	−0.0001 (11)	−0.0065 (10)
C17	0.0478 (14)	0.0373 (13)	0.0300 (12)	−0.0120 (11)	0.0034 (10)	0.0064 (10)
C18	0.0350 (12)	0.0305 (12)	0.0448 (13)	−0.0101 (10)	−0.0005 (10)	−0.0107 (10)
C19	0.0431 (13)	0.0345 (12)	0.0279 (11)	−0.0098 (10)	0.0052 (9)	−0.0017 (9)
N1	0.0291 (9)	0.0177 (8)	0.0277 (9)	−0.0016 (7)	−0.0018 (7)	−0.0001 (7)
N2	0.0309 (9)	0.0199 (8)	0.0245 (9)	−0.0015 (7)	0.0001 (7)	−0.0013 (7)
O1	0.0480 (10)	0.0232 (8)	0.0325 (8)	−0.0107 (7)	0.0041 (7)	0.0023 (6)
O2	0.0520 (10)	0.0185 (7)	0.0355 (9)	−0.0018 (7)	−0.0072 (7)	−0.0029 (6)
O3	0.0388 (9)	0.0246 (8)	0.0278 (8)	−0.0043 (6)	0.0048 (6)	−0.0035 (6)
O4	0.0367 (8)	0.0168 (7)	0.0262 (7)	−0.0013 (6)	0.0029 (6)	−0.0010 (5)
O5	0.0531 (10)	0.0255 (8)	0.0416 (10)	−0.0062 (7)	−0.0027 (8)	−0.0096 (7)

Geometric parameters (Å, º) top

Cl1—C11	1.730 (2)	C11—C12	1.394 (3)
Cl2—C12	1.734 (2)	C12—C13	1.378 (3)
C1—C6	1.387 (3)	C13—C14	1.388 (3)
C1—C2	1.392 (3)	C13—H13	0.9500
C1—C7	1.465 (3)	C14—H14	0.9500
C2—C3	1.388 (3)	C15—O5	1.224 (3)
C2—H2	0.9500	C15—N2	1.360 (3)
C3—O1	1.367 (2)	C15—C16	1.501 (3)
C3—C4	1.404 (3)	C16—H16A	0.9800
C4—O2	1.370 (2)	C16—H16B	0.9800
C4—C5	1.392 (3)	C16—H16C	0.9800
C5—O3	1.364 (2)	C17—O1	1.429 (3)
C5—C6	1.394 (3)	C17—H17A	0.9800
C6—H6	0.9500	C17—H17B	0.9800
C7—N1	1.277 (3)	C17—H17C	0.9800
C7—O4	1.368 (2)	C18—O2	1.438 (3)
C8—O4	1.446 (2)	C18—H18A	0.9800
C8—N2	1.476 (3)	C18—H18B	0.9800
C8—C9	1.506 (3)	C18—H18C	0.9800
C8—H8	1.0000	C19—O3	1.429 (3)
C9—C10	1.390 (3)	C19—H19A	0.9800
C9—C14	1.391 (3)	C19—H19B	0.9800
C10—C11	1.385 (3)	C19—H19C	0.9800
C10—H10	0.9500	N1—N2	1.409 (2)

C6—C1—C2	121.40 (18)	C12—C13—H13	120.3
C6—C1—C7	119.20 (18)	C14—C13—H13	120.3
C2—C1—C7	119.32 (18)	C13—C14—C9	120.8 (2)
C3—C2—C1	118.83 (19)	C13—C14—H14	119.6
C3—C2—H2	120.6	C9—C14—H14	119.6
C1—C2—H2	120.6	O5—C15—N2	119.3 (2)
O1—C3—C2	124.24 (19)	O5—C15—C16	123.7 (2)
O1—C3—C4	115.06 (18)	N2—C15—C16	117.0 (2)
C2—C3—C4	120.70 (18)	C15—C16—H16A	109.5
O2—C4—C5	122.30 (19)	C15—C16—H16B	109.5
O2—C4—C3	118.03 (18)	H16A—C16—H16B	109.5
C5—C4—C3	119.42 (18)	C15—C16—H16C	109.5
O3—C5—C4	115.61 (18)	H16A—C16—H16C	109.5
O3—C5—C6	124.10 (19)	H16B—C16—H16C	109.5
C4—C5—C6	120.27 (19)	O1—C17—H17A	109.5
C1—C6—C5	119.37 (19)	O1—C17—H17B	109.5
C1—C6—H6	120.3	H17A—C17—H17B	109.5
C5—C6—H6	120.3	O1—C17—H17C	109.5
N1—C7—O4	116.60 (17)	H17A—C17—H17C	109.5
N1—C7—C1	126.14 (18)	H17B—C17—H17C	109.5
O4—C7—C1	117.22 (17)	O2—C18—H18A	109.5
O4—C8—N2	100.90 (14)	O2—C18—H18B	109.5
O4—C8—C9	110.42 (16)	H18A—C18—H18B	109.5
N2—C8—C9	113.01 (16)	O2—C18—H18C	109.5
O4—C8—H8	110.7	H18A—C18—H18C	109.5
N2—C8—H8	110.7	H18B—C18—H18C	109.5
C9—C8—H8	110.7	O3—C19—H19A	109.5
C10—C9—C14	119.51 (18)	O3—C19—H19B	109.5
C10—C9—C8	120.30 (18)	H19A—C19—H19B	109.5
C14—C9—C8	120.18 (18)	O3—C19—H19C	109.5
C11—C10—C9	119.63 (19)	H19A—C19—H19C	109.5
C11—C10—H10	120.2	H19B—C19—H19C	109.5
C9—C10—H10	120.2	C7—N1—N2	104.79 (16)
C10—C11—C12	120.43 (19)	C15—N2—N1	123.09 (17)
C10—C11—Cl1	118.75 (16)	C15—N2—C8	121.12 (17)
C12—C11—Cl1	120.82 (16)	N1—N2—C8	110.70 (15)
C13—C12—C11	120.13 (19)	C3—O1—C17	117.06 (17)
C13—C12—Cl2	119.37 (16)	C4—O2—C18	116.81 (17)
C11—C12—Cl2	120.49 (17)	C5—O3—C19	117.18 (16)
C12—C13—C14	119.45 (19)	C7—O4—C8	106.95 (15)

C6—C1—C2—C3	1.4 (3)	C10—C11—C12—Cl2	−178.89 (16)
C7—C1—C2—C3	−175.26 (18)	Cl1—C11—C12—Cl2	1.2 (3)
C1—C2—C3—O1	179.76 (19)	C11—C12—C13—C14	−0.4 (3)
C1—C2—C3—C4	−0.2 (3)	Cl2—C12—C13—C14	179.24 (16)
O1—C3—C4—O2	−6.1 (3)	C12—C13—C14—C9	0.0 (3)
C2—C3—C4—O2	173.88 (18)	C10—C9—C14—C13	0.0 (3)
O1—C3—C4—C5	179.51 (18)	C8—C9—C14—C13	−179.09 (19)
C2—C3—C4—C5	−0.5 (3)	O4—C7—N1—N2	−0.3 (2)
O2—C4—C5—O3	4.6 (3)	C1—C7—N1—N2	177.36 (18)
C3—C4—C5—O3	178.68 (18)	O5—C15—N2—N1	165.36 (19)
O2—C4—C5—C6	−174.01 (18)	C16—C15—N2—N1	−16.2 (3)
C3—C4—C5—C6	0.1 (3)	O5—C15—N2—C8	12.9 (3)
C2—C1—C6—C5	−1.8 (3)	C16—C15—N2—C8	−168.66 (19)
C7—C1—C6—C5	174.89 (18)	C7—N1—N2—C15	−153.3 (2)
O3—C5—C6—C1	−177.46 (18)	C7—N1—N2—C8	1.6 (2)
C4—C5—C6—C1	1.0 (3)	O4—C8—N2—C15	153.32 (18)
C6—C1—C7—N1	−169.31 (19)	C9—C8—N2—C15	−88.8 (2)
C2—C1—C7—N1	7.4 (3)	O4—C8—N2—N1	−2.2 (2)
C6—C1—C7—O4	8.3 (3)	C9—C8—N2—N1	115.70 (18)
C2—C1—C7—O4	−174.95 (17)	C2—C3—O1—C17	−9.0 (3)
O4—C8—C9—C10	45.1 (2)	C4—C3—O1—C17	171.03 (19)
N2—C8—C9—C10	−67.1 (2)	C5—C4—O2—C18	−65.1 (3)
O4—C8—C9—C14	−135.80 (19)	C3—C4—O2—C18	120.8 (2)
N2—C8—C9—C14	112.0 (2)	C4—C5—O3—C19	−172.83 (18)
C14—C9—C10—C11	0.3 (3)	C6—C5—O3—C19	5.7 (3)
C8—C9—C10—C11	179.43 (18)	N1—C7—O4—C8	−1.2 (2)
C9—C10—C11—C12	−0.7 (3)	C1—C7—O4—C8	−179.02 (17)
C9—C10—C11—Cl1	179.22 (15)	N2—C8—O4—C7	1.92 (19)
C10—C11—C12—C13	0.7 (3)	C9—C8—O4—C7	−117.85 (17)
Cl1—C11—C12—C13	−179.17 (16)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C6—H6···O4	0.95	2.43	2.772 (2)	101
C8—H8···O2ⁱ	1.00	2.56	3.184 (3)	121
C10—H10···O1ⁱⁱ	0.95	2.43	3.302 (3)	153
C13—H13···O5ⁱⁱⁱ	0.95	2.53	3.426 (3)	156
C16—H16B···N1	0.98	2.42	2.839 (3)	105
C18—H18A···N1ⁱⁱ	0.98	2.53	3.468 (3)	160
C18—H18C···O3	0.98	2.36	2.916 (3)	116
C19—H19A···O5^iv	0.98	2.58	3.233 (3)	124

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

Experimental details

Crystal data
Chemical formula	C₁₉H₁₈Cl₂N₂O₅
M_r	425.25
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	173
a, b, c (Å)	7.6743 (4), 15.9516 (8), 15.7483 (8)
β (°)	90.894 (1)
V (Å³)	1927.63 (17)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.37
Crystal size (mm)	0.47 × 0.39 × 0.32

Data collection
Diffractometer	Bruker SMART 1000 CCD diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 2003)
T_min, T_max	0.845, 0.891
No. of measured, independent and observed [I > 2σ(I)] reflections	10032, 4159, 3238
R_int	0.025
(sin θ/λ)_max (Å⁻¹)	0.642

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.041, 0.125, 1.04
No. of reflections	4159
No. of parameters	257
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.34, −0.31

Computer programs: SMART (Bruker, 2001), SAINT-Plus (Bruker, 2003), SHELXTL (Sheldrick, 2008).