3-(2,4-Dichloro­phen­yl)-5-methyl-1,2,4-oxadiazole

In the title compound, C₉H₆Cl₂N₂O, the dihedral angle between the oxadiazole and benzene rings is 1.7 (2)°. In the crystal, the mol­ecules are linked into chains along the b axis by short inter­molecular Cl...O contacts [3.019 (3) Å].

Key indicators

• Single-crystal X-ray study
• T = 100 K
• Mean [sigma](C-C) = 0.005 Å
• R factor = 0.056
• wR factor = 0.155
• Data-to-parameter ratio = 16.2

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT340_ALERT_3_C Low Bond Precision on  C-C Bonds (x 1000) Ang ..          6
PLAT431_ALERT_2_C Short Inter HL..A Contact  Cl2    ..  O1      ..       3.02 Ang.
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.600         11

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

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

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S1. Comment

Heterocyclic compounds are important in recent years due to pharmacological activities. Nitrogen, oxygen containing five- and six-membered heterocyclic compounds have enormous significance in the field of medicinal chemistry. Oxadiazoles play a very vital role in the preparation of various biologically active drugs with anti-inflammatory (Andersen et al., 1994), anti-cancer (Showell et al., 1991), anti-HIV (Watjen et al., 1989), anti-diabetic and anti-microbial (Swain et al., 1991) properties. The results of biological studies showed that oxadiazole derivatives are molecules with maximum anti-inflammatory, analgesic and minimum ulcerogenic and lipid per-oxidation (Clitherow et al., 1996) properties.

Bond lengths and angles are normal (Wang et al., 2006). The mean plane of the oxadiazole ring (C1/C2/N1/N2/O1) is almost coplanar with the mean plane of the C3–C8 benzene ring (Fig. 1), with a dihedral angle of 1.7 (2)°.

The molecules are linked by Cl2···O1(-x, 1/2+y, 3/2-z) short contacts [3.019 (3) Å;] to form chains along the b axis (Fig.2).

Related literature

For general background and the biological activity of oxadiazole compounds, see: Andersen et al. (1994); Clitherow et al. (1996); Showell et al. (1991); Swain et al. (1991); Watjen et al. (1989). For a related structure, see: Wang et al. (2006). For the stability of the temperature controller used for the data collection, see: Cosier & Glazer (1986).

S2. Experimental

The title compound was prepared by heating a solution of 2,4-dichloro-N'-hydroxy-benzamidine (1 g, 0.0042 mol) and acetyl chloride (0.38 g, 0.004 mol) in pyridine (30 ml) at 387 K for 1.5 h and the contents were concentrated under vacuum. Further purification was done by column chromatography. The solid obtained was recrystallized using dichloromethane (yield: 1.0 g (76%); m.p. 371-372 K).

S3. Refinement

H atoms were placed in calculated positions [C–H = 0.93–0.96 Å] and refined as riding with U_iso(H) = 1.2_eq(C) or 1.5U_eq(methyl C). A rotating group model was used for the methyl group.

Computing details

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (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, 2009).

Figures

	Fig. 1. The molecular structure of the title compound, showing 50% probability displacement ellipsoids and the atom-numbering scheme.
	Fig. 2. The crystal structure of the title compound, showing chains along the b axis.

3-(2,4-Dichlorophenyl)-5-methyl-1,2,4-oxadiazole

Crystal data

C9H6Cl2N2O	F(000) = 464
Mr = 229.06	Dx = 1.657 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 3719 reflections
a = 3.8252 (7) Å	θ = 2.6–31.1°
b = 21.678 (4) Å	µ = 0.67 mm^−1
c = 11.0833 (19) Å	T = 100 K
β = 92.421 (4)°	Block, colourless
V = 918.3 (3) Å^3	0.28 × 0.17 × 0.11 mm
Z = 4

Data collection

Bruker SMART APEXII CCD area-detector diffractometer	2076 independent reflections
Radiation source: fine-focus sealed tube	1709 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.048
ϕ and ω scans	θmax = 27.5°, θmin = 1.9°
Absorption correction: multi-scan (SADABS; Bruker, 2005)	h = −4→4
Tmin = 0.833, Tmax = 0.929	k = −26→28
7920 measured reflections	l = −13→14

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.056	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.155	H-atom parameters constrained
S = 1.20	w = 1/[σ^2(Fo^2) + (0.0428P)^2 + 4.0517P] where P = (Fo^2 + 2Fc^2)/3
2076 reflections	(Δ/σ)max = 0.001
128 parameters	Δρmax = 0.72 e Å^−3
0 restraints	Δρmin = −0.56 e Å^−3

Special details

Experimental. The crystal was placed in the cold stream of an Oxford Cyrosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) K.

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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 (Ų)

	x	y	z	Uiso*/Ueq
Cl1	0.2530 (2)	0.40084 (4)	0.92173 (8)	0.0163 (2)
Cl2	0.1238 (3)	0.63730 (4)	0.78985 (9)	0.0185 (3)
O1	−0.2054 (8)	0.27327 (13)	0.6574 (3)	0.0220 (7)
N1	−0.3467 (8)	0.35961 (15)	0.5636 (3)	0.0158 (7)
N2	−0.0709 (10)	0.32171 (16)	0.7322 (3)	0.0194 (7)
C1	−0.3637 (11)	0.30045 (18)	0.5605 (4)	0.0173 (8)
C2	−0.1651 (10)	0.37119 (18)	0.6715 (3)	0.0140 (8)
C3	−0.0869 (9)	0.43519 (17)	0.7088 (3)	0.0124 (7)
C4	0.0928 (10)	0.45392 (18)	0.8165 (3)	0.0137 (8)
C5	0.1523 (9)	0.51553 (18)	0.8418 (4)	0.0136 (7)
H5A	0.2684	0.5272	0.9136	0.016*
C6	0.0369 (10)	0.56000 (17)	0.7588 (3)	0.0127 (7)
C7	−0.1429 (10)	0.54398 (18)	0.6533 (4)	0.0151 (8)
H7A	−0.2240	0.5740	0.5990	0.018*
C8	−0.1993 (10)	0.48214 (18)	0.6303 (4)	0.0153 (8)
H8A	−0.3186	0.4712	0.5586	0.018*
C9	−0.5226 (12)	0.2592 (2)	0.4666 (4)	0.0237 (9)
H9A	−0.6428	0.2835	0.4055	0.036*
H9B	−0.6856	0.2319	0.5028	0.036*
H9C	−0.3422	0.2354	0.4308	0.036*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl1	0.0168 (5)	0.0182 (5)	0.0138 (5)	0.0028 (3)	−0.0011 (3)	0.0023 (4)
Cl2	0.0197 (5)	0.0140 (4)	0.0219 (5)	−0.0024 (3)	0.0025 (4)	−0.0017 (4)
O1	0.0309 (17)	0.0139 (14)	0.0213 (15)	−0.0017 (12)	0.0017 (12)	−0.0018 (12)
N1	0.0130 (15)	0.0175 (16)	0.0172 (17)	0.0000 (12)	0.0018 (12)	−0.0022 (13)
N2	0.0257 (19)	0.0147 (16)	0.0178 (18)	−0.0002 (14)	0.0018 (14)	−0.0032 (13)
C1	0.0148 (19)	0.0194 (19)	0.018 (2)	0.0000 (15)	0.0051 (15)	−0.0007 (15)
C2	0.0103 (17)	0.0185 (19)	0.0138 (18)	0.0022 (14)	0.0081 (14)	0.0000 (14)
C3	0.0078 (17)	0.0152 (18)	0.0150 (18)	0.0009 (13)	0.0080 (14)	−0.0011 (14)
C4	0.0126 (18)	0.0171 (19)	0.0119 (19)	0.0043 (13)	0.0054 (14)	0.0016 (14)
C5	0.0070 (16)	0.0208 (19)	0.0132 (18)	0.0017 (14)	0.0022 (13)	−0.0021 (15)
C6	0.0106 (17)	0.0134 (17)	0.0144 (18)	−0.0008 (13)	0.0033 (13)	−0.0027 (14)
C7	0.0106 (18)	0.0174 (19)	0.0177 (19)	0.0033 (14)	0.0056 (14)	0.0033 (15)
C8	0.0114 (17)	0.0181 (19)	0.017 (2)	0.0005 (14)	0.0055 (14)	0.0004 (15)
C9	0.025 (2)	0.018 (2)	0.029 (2)	−0.0030 (16)	0.0041 (18)	−0.0072 (17)

Geometric parameters (Å, º)

Cl1—C4	1.732 (4)	C4—C5	1.382 (5)
Cl2—C6	1.740 (4)	C5—C6	1.391 (5)
O1—C1	1.346 (5)	C5—H5A	0.93
O1—N2	1.421 (4)	C6—C7	1.376 (5)
N1—C1	1.285 (5)	C7—C8	1.380 (6)
N1—C2	1.381 (5)	C7—H7A	0.93
N2—C2	1.308 (5)	C8—H8A	0.93
C1—C9	1.483 (6)	C9—H9A	0.96
C2—C3	1.475 (5)	C9—H9B	0.96
C3—C8	1.396 (5)	C9—H9C	0.96
C3—C4	1.411 (5)
C1—O1—N2	106.4 (3)	C6—C5—H5A	120.3
C1—N1—C2	103.2 (3)	C7—C6—C5	121.3 (4)
C2—N2—O1	102.8 (3)	C7—C6—Cl2	119.7 (3)
N1—C1—O1	113.3 (4)	C5—C6—Cl2	119.0 (3)
N1—C1—C9	129.8 (4)	C6—C7—C8	118.1 (4)
O1—C1—C9	116.9 (4)	C6—C7—H7A	121.0
N2—C2—N1	114.4 (4)	C8—C7—H7A	121.0
N2—C2—C3	125.4 (4)	C7—C8—C3	123.5 (4)
N1—C2—C3	120.2 (3)	C7—C8—H8A	118.3
C8—C3—C4	116.4 (3)	C3—C8—H8A	118.3
C8—C3—C2	117.2 (3)	C1—C9—H9A	109.5
C4—C3—C2	126.4 (3)	C1—C9—H9B	109.5
C5—C4—C3	121.3 (3)	H9A—C9—H9B	109.5
C5—C4—Cl1	117.1 (3)	C1—C9—H9C	109.5
C3—C4—Cl1	121.6 (3)	H9A—C9—H9C	109.5
C4—C5—C6	119.4 (3)	H9B—C9—H9C	109.5
C4—C5—H5A	120.3
C1—O1—N2—C2	0.1 (4)	C8—C3—C4—C5	0.0 (5)
C2—N1—C1—O1	−0.4 (5)	C2—C3—C4—C5	179.8 (3)
C2—N1—C1—C9	−179.1 (4)	C8—C3—C4—Cl1	−179.1 (3)
N2—O1—C1—N1	0.2 (5)	C2—C3—C4—Cl1	0.6 (5)
N2—O1—C1—C9	179.1 (3)	C3—C4—C5—C6	−0.8 (6)
O1—N2—C2—N1	−0.4 (4)	Cl1—C4—C5—C6	178.4 (3)
O1—N2—C2—C3	−179.3 (3)	C4—C5—C6—C7	1.6 (6)
C1—N1—C2—N2	0.5 (5)	C4—C5—C6—Cl2	−178.3 (3)
C1—N1—C2—C3	179.5 (3)	C5—C6—C7—C8	−1.5 (6)
N2—C2—C3—C8	178.0 (4)	Cl2—C6—C7—C8	178.4 (3)
N1—C2—C3—C8	−0.8 (5)	C6—C7—C8—C3	0.7 (6)
N2—C2—C3—C4	−1.8 (6)	C4—C3—C8—C7	0.1 (6)
N1—C2—C3—C4	179.4 (4)	C2—C3—C8—C7	−179.7 (4)