1-[5-(2-Chloro­pyridin-3-yl)-2-methyl-2-phenyl-1,3,4-oxadiazol-3(2H)-yl]ethanone

In the title compound, C₁₆H₁₄ClN₃O₂, all bond lengths and angles are normal. The mean plane of the oxadiazo­line ring makes dihedral angles of 1.94 (3) and 82.05 (3)° with the substituted pyridine and benzene rings, respectively. No classical hydrogen bonds are evident in the crystal packing.

Key indicators

• Single-crystal X-ray study
• T = 273 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.036
• wR factor = 0.105
• Data-to-parameter ratio = 18.6

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT031_ALERT_4_C Refined Extinction Parameter within Range ......       3.25 Sigma
PLAT066_ALERT_1_C Predicted and Reported Transmissions Identical .          ?
PLAT230_ALERT_2_C Hirshfeld Test Diff for    C14    -   C15     ..       5.23 su

Alert level G
PLAT793_ALERT_1_G Check the Absolute Configuration of C7     = ...          R

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

   2 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
   0 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

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S1. Comment

In continuation of our study of 1,3,4-oxadiazolines (Song, Zhang, Dong et al., 2006; Song, Zhang & Tiekink, 2006), which possess a wide range of pharmaceutical activities (Hassan et al., 1983; Khalil et al., 1993), we present here the crystal structure of the title compound, (I).

In (I) (Fig. 1), all bond lengths and angles are normal (Allen et al., 1987). The molecule is twisted around the C7—C11 bond. Within the five-membered oxadiazoline ring, there is a formal C6=N2 double bond (1.2755 (17) Å), the bond C6—O2 [1.3648 (16) Å] is shortened as compared with C7—O2 [1.4615 (16) Å], showing some delocalization of electron density over the O2—C6—N2 chromophore.

Related literature

For the crystal structures of isomers of the title compound, see: Song, Zhang, Dong et al. (2006); Song, Zhang & Tiekink (2006). For the pharmacological properties of 2,5-disubstituted 1,3,4-oxadiazolines, see: Hassan et al. (1983); Khalil et al. (1993). For the normal values of bond lengths and angles in organic compounds, see: Allen et al. (1987).

S2. Experimental

A solution of 2-chloropyridine-3-carboxylic acid phenylethylidene hydrazide (0.5 g, 1.91 mmol) in 10 ml of acetic anhydride was refluxed until the reaction was finished. The acetic anhydride was distilled in vacuum. The residue was recrystallized from ethanol (10 ml). Colourless crystals (0.38 g) of the title compound were obtained by slow evaporation of the solvent after 2 days at room temperature.

S3. Refinement

H atoms were placed in calculated positions and allowed to ride on their parent atoms, with C—H = 0.93–0.96 Å and U_iso(H) = 1.2Ueq(C) or 1.5Ueq(C_methyl).

Computing details

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT (Bruker, 2000); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 2000); software used to prepare material for publication: SHELXTL (Bruker, 2000).

Figures

	Fig. 1. The molecular structure of (I) showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 40% probability level.
	Fig. 2. The molecular packing viewed along the a axis. H atoms omitted for clarity.

1-[5-(2-Chloropyridin-3-yl)-2-methyl-2-phenyl-1,3,4-oxadiazol-3(2H)-yl]ethanone

Crystal data

C16H14ClN3O2	F(000) = 656
Mr = 315.75	Dx = 1.371 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 4932 reflections
a = 7.7788 (7) Å	θ = 2.6–27.6°
b = 24.625 (2) Å	µ = 0.26 mm^−1
c = 7.9948 (8) Å	T = 273 K
β = 93.030 (1)°	Block, colourless
V = 1529.3 (2) Å^3	0.12 × 0.10 × 0.08 mm
Z = 4

Data collection

Bruker APEXII CCD area-detector diffractometer	3751 independent reflections
Radiation source: fine-focus sealed tube	2953 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.019
φ and ω scans	θmax = 28.2°, θmin = 2.6°
Absorption correction: multi-scan (SADABS; Bruker, 2000)	h = −10→10
Tmin = 0.970, Tmax = 0.980	k = −32→32
13995 measured reflections	l = −10→10

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.036	H-atom parameters not refined
wR(F^2) = 0.105	w = 1/[σ^2(Fo^2) + (0.0526P)^2 + 0.2948P] where P = (Fo^2 + 2Fc^2)/3
S = 1.00	(Δ/σ)max < 0.001
3751 reflections	Δρmax = 0.21 e Å^−3
202 parameters	Δρmin = −0.25 e Å^−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 1997), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0039 (12)

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
C1	0.28346 (18)	0.52714 (5)	−0.02816 (18)	0.0444 (3)
C2	0.27771 (17)	0.50607 (5)	0.13417 (17)	0.0412 (3)
C3	0.3456 (2)	0.53918 (6)	0.2626 (2)	0.0546 (4)
H3	0.3440	0.5276	0.3732	0.066*
C4	0.4152 (2)	0.58909 (7)	0.2260 (2)	0.0653 (4)
H4	0.4613	0.6114	0.3107	0.078*
C5	0.4145 (2)	0.60475 (7)	0.0619 (2)	0.0668 (5)
H5	0.4621	0.6383	0.0375	0.080*
C6	0.20863 (17)	0.45270 (5)	0.17689 (16)	0.0415 (3)
C7	0.14495 (19)	0.38600 (5)	0.36193 (16)	0.0448 (4)
C8	0.01531 (18)	0.32860 (5)	0.12329 (17)	0.0443 (3)
C9	−0.0074 (2)	0.32372 (7)	−0.06330 (19)	0.0611 (4)
H9A	0.1034	0.3215	−0.1103	0.092*
H9B	−0.0680	0.3550	−0.1076	0.092*
H9C	−0.0723	0.2915	−0.0915	0.092*
C10	−0.0073 (2)	0.39235 (7)	0.47005 (19)	0.0563 (4)
H10A	0.0315	0.4056	0.5785	0.084*
H10B	−0.0627	0.3578	0.4818	0.084*
H10C	−0.0876	0.4177	0.4185	0.084*
C11	0.28433 (17)	0.34702 (5)	0.42702 (16)	0.0419 (3)
C12	0.2521 (2)	0.30728 (6)	0.54395 (18)	0.0528 (4)
H12	0.1425	0.3042	0.5844	0.063*
C13	0.3805 (2)	0.27214 (7)	0.6013 (2)	0.0667 (5)
H13	0.3576	0.2463	0.6821	0.080*
C14	0.5419 (2)	0.27503 (7)	0.5398 (2)	0.0674 (5)
H14	0.6281	0.2513	0.5784	0.081*
C15	0.5750 (2)	0.31361 (8)	0.4199 (2)	0.0640 (5)
H15	0.6832	0.3153	0.3759	0.077*
C16	0.4476 (2)	0.34980 (7)	0.36515 (18)	0.0530 (4)
H16	0.4717	0.3761	0.2864	0.064*
Cl1	0.20295 (6)	0.491105 (16)	−0.20175 (5)	0.06009 (14)
N1	0.34943 (18)	0.57466 (5)	−0.06525 (18)	0.0590 (3)
N2	0.13810 (15)	0.41731 (4)	0.07904 (14)	0.0432 (3)
N3	0.09365 (16)	0.37466 (5)	0.18324 (14)	0.0463 (3)
O1	−0.02848 (15)	0.29362 (4)	0.22043 (13)	0.0579 (3)
O2	0.22132 (15)	0.43973 (4)	0.34306 (12)	0.0540 (3)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0459 (7)	0.0390 (7)	0.0489 (7)	0.0045 (5)	0.0094 (6)	0.0056 (6)
C2	0.0427 (7)	0.0353 (6)	0.0460 (7)	0.0014 (5)	0.0052 (5)	0.0023 (5)
C3	0.0667 (10)	0.0438 (8)	0.0533 (8)	−0.0054 (7)	0.0025 (7)	−0.0007 (6)
C4	0.0774 (11)	0.0456 (8)	0.0727 (11)	−0.0125 (8)	0.0023 (9)	−0.0081 (8)
C5	0.0770 (11)	0.0414 (8)	0.0832 (12)	−0.0122 (8)	0.0152 (9)	0.0062 (8)
C6	0.0488 (7)	0.0384 (7)	0.0373 (6)	0.0001 (5)	0.0032 (5)	0.0039 (5)
C7	0.0613 (11)	0.0386 (9)	0.0344 (8)	−0.0103 (8)	0.0008 (7)	0.0020 (7)
C8	0.0501 (7)	0.0391 (7)	0.0435 (7)	−0.0024 (6)	0.0012 (6)	0.0001 (5)
C9	0.0839 (11)	0.0541 (9)	0.0447 (8)	−0.0056 (8)	−0.0037 (7)	−0.0077 (7)
C10	0.0645 (10)	0.0585 (9)	0.0464 (8)	0.0053 (7)	0.0071 (7)	0.0031 (7)
C11	0.0498 (7)	0.0417 (7)	0.0341 (6)	−0.0089 (6)	0.0006 (5)	−0.0002 (5)
C12	0.0547 (8)	0.0537 (9)	0.0503 (8)	−0.0033 (7)	0.0047 (6)	0.0130 (7)
C13	0.0710 (11)	0.0582 (10)	0.0700 (11)	0.0022 (8)	−0.0035 (9)	0.0183 (8)
C14	0.0628 (10)	0.0606 (10)	0.0771 (12)	0.0071 (8)	−0.0119 (9)	−0.0054 (9)
C15	0.0471 (8)	0.0777 (12)	0.0675 (10)	−0.0087 (8)	0.0041 (7)	−0.0211 (9)
C16	0.0563 (9)	0.0599 (9)	0.0431 (7)	−0.0147 (7)	0.0068 (6)	−0.0028 (6)
Cl1	0.0826 (3)	0.0537 (2)	0.0438 (2)	−0.00125 (18)	0.00217 (18)	0.00691 (15)
N1	0.0705 (9)	0.0428 (7)	0.0650 (8)	−0.0036 (6)	0.0162 (7)	0.0106 (6)
N2	0.0534 (7)	0.0389 (6)	0.0373 (6)	−0.0043 (5)	0.0033 (5)	0.0062 (4)
N3	0.0637 (7)	0.0406 (6)	0.0340 (5)	−0.0109 (5)	−0.0017 (5)	0.0051 (4)
O1	0.0746 (7)	0.0450 (6)	0.0541 (6)	−0.0142 (5)	0.0051 (5)	0.0044 (5)
O2	0.0836 (7)	0.0399 (5)	0.0376 (5)	−0.0148 (5)	−0.0035 (5)	0.0035 (4)

Geometric parameters (Å, º)

C1—N1	1.3179 (18)	C8—C9	1.498 (2)
C1—C2	1.4006 (19)	C9—H9A	0.9600
C1—Cl1	1.7360 (15)	C9—H9B	0.9600
C2—C3	1.393 (2)	C9—H9C	0.9600
C2—C6	1.4670 (18)	C10—H10A	0.9600
C3—C4	1.380 (2)	C10—H10B	0.9600
C3—H3	0.9300	C10—H10C	0.9600
C4—C5	1.367 (3)	C11—C12	1.3854 (19)
C4—H4	0.9300	C11—C16	1.389 (2)
C5—N1	1.336 (2)	C12—C13	1.382 (2)
C5—H5	0.9300	C12—H12	0.9300
C6—N2	1.2755 (17)	C13—C14	1.374 (3)
C6—O2	1.3648 (16)	C13—H13	0.9300
C7—O2	1.4615 (16)	C14—C15	1.383 (3)
C7—N3	1.4892 (16)	C14—H14	0.9300
C7—C10	1.511 (2)	C15—C16	1.387 (2)
C7—C11	1.519 (2)	C15—H15	0.9300
C8—O1	1.2203 (17)	C16—H16	0.9300
C8—N3	1.3626 (17)	N2—N3	1.3953 (15)
N1—C1—C2	124.70 (14)	H9B—C9—H9C	109.5
N1—C1—Cl1	113.72 (11)	C7—C10—H10A	109.5
C2—C1—Cl1	121.58 (11)	C7—C10—H10B	109.5
C3—C2—C1	115.89 (13)	H10A—C10—H10B	109.5
C3—C2—C6	118.83 (12)	C7—C10—H10C	109.5
C1—C2—C6	125.28 (12)	H10A—C10—H10C	109.5
C4—C3—C2	120.19 (15)	H10B—C10—H10C	109.5
C4—C3—H3	119.9	C12—C11—C16	118.48 (14)
C2—C3—H3	119.9	C12—C11—C7	121.73 (13)
C5—C4—C3	118.21 (16)	C16—C11—C7	119.76 (12)
C5—C4—H4	120.9	C13—C12—C11	120.83 (15)
C3—C4—H4	120.9	C13—C12—H12	119.6
N1—C5—C4	123.77 (15)	C11—C12—H12	119.6
N1—C5—H5	118.1	C14—C13—C12	120.50 (16)
C4—C5—H5	118.1	C14—C13—H13	119.8
N2—C6—O2	116.35 (11)	C12—C13—H13	119.8
N2—C6—C2	128.33 (12)	C13—C14—C15	119.38 (16)
O2—C6—C2	115.32 (11)	C13—C14—H14	120.3
O2—C7—N3	99.23 (9)	C15—C14—H14	120.3
O2—C7—C10	107.49 (12)	C14—C15—C16	120.27 (16)
N3—C7—C10	112.94 (12)	C14—C15—H15	119.9
O2—C7—C11	108.71 (11)	C16—C15—H15	119.9
N3—C7—C11	111.13 (11)	C15—C16—C11	120.51 (15)
C10—C7—C11	115.87 (12)	C15—C16—H16	119.7
O1—C8—N3	119.90 (13)	C11—C16—H16	119.7
O1—C8—C9	123.70 (13)	C1—N1—C5	117.24 (14)
N3—C8—C9	116.38 (12)	C6—N2—N3	105.08 (10)
C8—C9—H9A	109.5	C8—N3—N2	122.46 (11)
C8—C9—H9B	109.5	C8—N3—C7	125.85 (11)
H9A—C9—H9B	109.5	N2—N3—C7	111.68 (10)
C8—C9—H9C	109.5	C6—O2—C7	107.66 (10)
H9A—C9—H9C	109.5
N1—C1—C2—C3	0.9 (2)	C12—C11—C16—C15	−0.2 (2)
Cl1—C1—C2—C3	−179.60 (11)	C7—C11—C16—C15	−178.30 (13)
N1—C1—C2—C6	−178.39 (14)	C2—C1—N1—C5	−0.3 (2)
Cl1—C1—C2—C6	1.1 (2)	Cl1—C1—N1—C5	−179.82 (12)
C1—C2—C3—C4	−0.9 (2)	C4—C5—N1—C1	−0.4 (3)
C6—C2—C3—C4	178.49 (15)	O2—C6—N2—N3	0.54 (16)
C2—C3—C4—C5	0.3 (3)	C2—C6—N2—N3	−179.11 (13)
C3—C4—C5—N1	0.4 (3)	O1—C8—N3—N2	−176.44 (13)
C3—C2—C6—N2	178.23 (14)	C9—C8—N3—N2	5.2 (2)
C1—C2—C6—N2	−2.5 (2)	O1—C8—N3—C7	4.6 (2)
C3—C2—C6—O2	−1.43 (19)	C9—C8—N3—C7	−173.76 (14)
C1—C2—C6—O2	177.89 (13)	C6—N2—N3—C8	−179.60 (13)
O2—C7—C11—C12	141.40 (13)	C6—N2—N3—C7	−0.53 (15)
N3—C7—C11—C12	−110.40 (14)	O2—C7—N3—C8	179.35 (13)
C10—C7—C11—C12	20.27 (19)	C10—C7—N3—C8	−67.11 (18)
O2—C7—C11—C16	−40.53 (16)	C11—C7—N3—C8	65.07 (17)
N3—C7—C11—C16	67.68 (15)	O2—C7—N3—N2	0.32 (14)
C10—C7—C11—C16	−161.65 (13)	C10—C7—N3—N2	113.86 (13)
C16—C11—C12—C13	1.8 (2)	C11—C7—N3—N2	−113.96 (12)
C7—C11—C12—C13	179.85 (15)	N2—C6—O2—C7	−0.35 (17)
C11—C12—C13—C14	−1.8 (3)	C2—C6—O2—C7	179.35 (11)
C12—C13—C14—C15	0.2 (3)	N3—C7—O2—C6	−0.01 (14)
C13—C14—C15—C16	1.4 (3)	C10—C7—O2—C6	−117.73 (12)
C14—C15—C16—C11	−1.4 (2)	C11—C7—O2—C6	116.13 (12)