3-Anilinomethyl-5-chloro-1,3-­benzoxazol-2(3H)-one

In the title compound, C₁₄H₁₁ClN₂O₂, the 2,3-dihydro-1,3-benzoxazole ring system is essentially planar [maximum deviation = 0.009 (2) Å] and makes a dihedral angle of 79.15 (7)° with the phenyl ring. Inter­molecular N—H...O and weak C—H...Cl hydrogen bonds occur in the crystal structure.

Key indicators

• Single-crystal X-ray study
• T = 296 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.043
• wR factor = 0.106
• Data-to-parameter ratio = 17.7

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT912_ALERT_4_C Missing # of FCF Reflections Above STh/L=  0.600          4

Alert level G
PLAT005_ALERT_5_G No _iucr_refine_instructions_details in CIF ....          ?
PLAT007_ALERT_5_G Note: Number of Unrefined D-H Atoms ............          1
PLAT063_ALERT_4_G Crystal Size Likely too Large for Beam Size ....       0.80 mm
PLAT128_ALERT_4_G Alternate Setting of Space-group P21/c   .......      P21/n

   0 ALERT level A = Most likely a serious problem - resolve or explain
   0 ALERT level B = A potentially serious problem, consider carefully
   1 ALERT level C = Check. Ensure it is not caused by an omission or oversight
   4 ALERT level G = General information/check it is not something unexpected

   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
   0 ALERT type 3 Indicator that the structure quality may be low
   3 ALERT type 4 Improvement, methodology, query or suggestion
   2 ALERT type 5 Informative message, check

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S1. Comment

The benzoxazolone nucleus represents an important pharmacophore present in pharmaceutical products. The compounds possessing this structure have a broad spectrum of biological activities, such as anti-HIV (Deng et al., 2006), anticancer (Ivanova et al., 2007), analgesic (Unlu et al., 2003), anti-inflammatory (Koksal et al., 2005), antinociceptive (Onkol et al., 2001), antimicrobial (Koksal et al., 2002), anticonvulsant (Ucar et al., 1998), antimalarial (Courtois et al., 2004), human leukocyte MPO clorinating inhibitor activity (Soyer et al., 2005).

In addition to, this compound was synthesized before by (Varma & Nobles, 1968) and they reported that most benzoxazolinone compounds have shown significant antibacterial activity.

In the title compound (I), (Fig. 1), the mean planes of the 2,3-dihydro-1,3-benzoxazole and phenyl rings make a dihedral angle of 79.15 (7)° with each other. The N1—C8—N2—C9 torsion angle is -72.99 (18)°. The bond lengths in (I) are normal and correspond to those observed in the related compound (Allen et al., 1987).

The Cl1—C3 and N1—C1 bond lengths are 1.7315 (16) Å, and 1.3914 (18) Å, respectively. The Cl1—C3—C4 and O2—C7—N1 bond angles are 118.73 (13) ° and 129.27 (15) °, respectively. The bond lengths and the bond angles of (I) are comparable to those observed in related structure (Aydın et al., 2004).

The crystal structure is stabilized by intermolecular N—H···O and C—H···Cl interactions (Table 1 and Fig. 2), connecting the molecules along the [001] direction.

Related literature

For the synthesis and biological activity of compounds with a benzoxazolone nucleus, see; Varma & Nobles (1968); Courtois et al. (2004); Deng et al. (2006); Ivanova et al. (2007); Koksal et al. (2002, 2005); Onkol et al. (2001); Soyer et al. (2005); Ucar et al. (1998); Unlu et al. (2003). For bond-length data, see: Allen et al. (1987). For a related structure, see: Aydın et al. (2004).

S2. Experimental

4-Chloro-2-aminophenol (10 mmol), urea (50 mmol) and 37% HCl (2.5 ml) were irradiated (300 W, 413 K) for 15 min in a microwave oven. After completion of reaction (by monitoring with TLC), water (10 ml) was added to the reaction mixture and stirred at room temperature for 1 h. The resulting precipitate was filtered and washed with water. The crude product crystallized from ethanol-water (1:1) to yield 5-chloro-2(3H)-benzoxazolone. This compound (2 mmol) was dissolved in methanol (5 ml). Aniline (2 mmol) and 37% formalin (2.5 mmol) were added to this solution. The mixture was stirred vigorously for 3 h. The resulting precipitate was filtered and washed with cold methanol. The crude product was crystallized from methanol.

M.p.: 463 K. Yield 84%; IR v_max (FTIR/ATR): 3398, 3066, 1750, 1604 cm^-1; ¹H-NMR (DMSO-d₆): δ 5.23 (2H, d, J=7.0 Hz, CH₂), 6.61(1H, t, J=7.4 Hz, H-Aniline), 6.73-6.75 (2H, m, H-Aniline), 6.96 (1H, t, J=7.3 Hz, NH), 7.09 (2H, t, J=7.4 Hz, H-Aniline) 7.14 (1H, dd, J=2.3; 8.6 Hz, H-Benzoxazolone), 7.31 (1H, d, J=8.6 Hz, H-Benzoxazolone), 7.70 (1H, d, J=2.3 Hz, H-Benzoxazolone) p.p.m.; MS (ESI) m/z (%): 275 (M+H, 11), 277 (M+H+2, 4).

S3. Refinement

H atoms were positioned geometrically and refined using a riding model with N—H = 0.86 Å, C—H = 0.93 and 0.97 Å, and U_iso(H) = 1.2U_eq(C,N).

Computing details

Data collection: X-AREA (Stoe & Cie, 2002); cell refinement: X-AREA (Stoe & Cie, 2002); data reduction: X-RED32 (Stoe & Cie, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999) and PLATON (Spek, 2009).

Figures

	Fig. 1. The molecule shown with the atom numbering scheme. Displacement ellipsoids for non-H atoms are drawn at the 50% probability level.
	Fig. 2. The packing and hydrogen bonding of (I) viewed down the a axis. H atoms not involved in hydrogen bondings are omitted for the sake of clarity.

3-Anilinomethyl-5-chloro-1,3-benzoxazol-2(3H)-one

Crystal data

C14H11ClN2O2	F(000) = 568
Mr = 274.70	Dx = 1.469 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 27572 reflections
a = 9.7379 (5) Å	θ = 2.1–28.6°
b = 12.4797 (7) Å	µ = 0.31 mm^−1
c = 10.2392 (7) Å	T = 296 K
β = 93.129 (5)°	Prism, colourless
V = 1242.48 (13) Å^3	0.80 × 0.48 × 0.26 mm
Z = 4

Data collection

Stoe IPDS 2 diffractometer	3051 independent reflections
Radiation source: sealed X-ray tube, 12 x 0.4 mm long-fine focus	2544 reflections with I > 2σ(I)
Plane graphite monochromator	Rint = 0.046
Detector resolution: 6.67 pixels mm^-1	θmax = 28.2°, θmin = 2.6°
ω scans	h = −12→12
Absorption correction: integration (X-RED32; Stoe & Cie, 2002)	k = −16→16
Tmin = 0.837, Tmax = 0.924	l = −13→13
20574 measured reflections

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)] = 0.043	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.106	H-atom parameters constrained
S = 1.07	w = 1/[σ^2(Fo^2) + (0.0456P)^2 + 0.2748P] where P = (Fo^2 + 2Fc^2)/3
3051 reflections	(Δ/σ)max < 0.001
172 parameters	Δρmax = 0.22 e Å^−3
0 restraints	Δρmin = −0.22 e Å^−3

Special details

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

Refinement. Refinement on F² for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The observed criterion of F² > σ(F²) is used only for calculating -R-factor-obs 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	0.37199 (5)	0.42730 (6)	−0.40607 (5)	0.0887 (2)
O1	0.61747 (10)	0.34298 (10)	0.11087 (11)	0.0535 (3)
O2	0.52561 (13)	0.24080 (12)	0.26644 (11)	0.0679 (4)
N1	0.41738 (11)	0.26396 (10)	0.06103 (11)	0.0428 (4)
N2	0.16989 (12)	0.24829 (12)	0.04683 (12)	0.0508 (4)
C1	0.45104 (13)	0.32285 (11)	−0.04809 (13)	0.0392 (4)
C2	0.38425 (14)	0.33757 (13)	−0.16827 (14)	0.0454 (4)
C3	0.45056 (16)	0.40463 (14)	−0.25277 (15)	0.0520 (5)
C4	0.57449 (16)	0.45354 (13)	−0.22095 (18)	0.0553 (5)
C5	0.64095 (15)	0.43708 (13)	−0.09935 (17)	0.0539 (5)
C6	0.57568 (14)	0.37153 (12)	−0.01549 (15)	0.0447 (4)
C7	0.51813 (15)	0.27708 (13)	0.15798 (15)	0.0495 (5)
C8	0.29647 (15)	0.19414 (13)	0.06944 (15)	0.0479 (5)
C9	0.11468 (13)	0.31842 (12)	0.13447 (13)	0.0422 (4)
C10	0.17189 (15)	0.33453 (13)	0.26004 (14)	0.0475 (4)
C11	0.10954 (17)	0.40404 (15)	0.34387 (16)	0.0565 (5)
C12	−0.00743 (18)	0.45947 (15)	0.30515 (19)	0.0624 (6)
C13	−0.06427 (19)	0.44406 (16)	0.1809 (2)	0.0659 (6)
C14	−0.00497 (17)	0.37461 (15)	0.09612 (16)	0.0567 (5)
H2	0.30060	0.30500	−0.19140	0.0550*
H2A	0.12430	0.23690	−0.02610	0.0610*
H4	0.61400	0.49800	−0.28140	0.0660*
H5	0.72520	0.46880	−0.07610	0.0650*
H8A	0.30210	0.13680	0.00590	0.0580*
H8B	0.29860	0.16180	0.15570	0.0580*
H10	0.25200	0.29870	0.28780	0.0570*
H11	0.14770	0.41340	0.42830	0.0680*
H12	−0.04750	0.50670	0.36210	0.0750*
H13	−0.14370	0.48100	0.15370	0.0790*
H14	−0.04490	0.36490	0.01240	0.0680*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl1	0.0635 (3)	0.1420 (6)	0.0602 (3)	0.0059 (3)	−0.0005 (2)	0.0431 (3)
O1	0.0397 (5)	0.0669 (7)	0.0528 (6)	−0.0022 (5)	−0.0074 (4)	−0.0061 (5)
O2	0.0674 (8)	0.0890 (9)	0.0457 (6)	0.0034 (7)	−0.0112 (5)	0.0084 (6)
N1	0.0373 (6)	0.0508 (7)	0.0399 (6)	−0.0004 (5)	−0.0007 (4)	0.0013 (5)
N2	0.0387 (6)	0.0736 (9)	0.0397 (6)	−0.0032 (6)	−0.0006 (5)	−0.0068 (6)
C1	0.0332 (6)	0.0416 (7)	0.0429 (7)	0.0030 (5)	0.0039 (5)	−0.0028 (6)
C2	0.0337 (6)	0.0572 (9)	0.0452 (7)	0.0012 (6)	0.0011 (5)	0.0028 (6)
C3	0.0433 (7)	0.0645 (10)	0.0486 (8)	0.0091 (7)	0.0050 (6)	0.0111 (7)
C4	0.0468 (8)	0.0528 (9)	0.0678 (10)	0.0010 (7)	0.0166 (7)	0.0096 (8)
C5	0.0391 (7)	0.0515 (9)	0.0716 (10)	−0.0055 (6)	0.0082 (7)	−0.0054 (8)
C6	0.0353 (6)	0.0478 (8)	0.0507 (8)	0.0027 (6)	0.0002 (6)	−0.0068 (6)
C7	0.0431 (7)	0.0582 (9)	0.0464 (8)	0.0066 (7)	−0.0044 (6)	−0.0024 (7)
C8	0.0477 (8)	0.0487 (8)	0.0476 (8)	−0.0050 (6)	0.0049 (6)	0.0000 (6)
C9	0.0365 (6)	0.0503 (8)	0.0400 (7)	−0.0100 (6)	0.0033 (5)	0.0036 (6)
C10	0.0385 (7)	0.0609 (9)	0.0427 (7)	−0.0069 (6)	−0.0008 (5)	0.0020 (7)
C11	0.0523 (9)	0.0708 (11)	0.0463 (8)	−0.0130 (8)	0.0010 (6)	−0.0104 (8)
C12	0.0565 (9)	0.0612 (10)	0.0704 (11)	−0.0046 (8)	0.0110 (8)	−0.0156 (9)
C13	0.0523 (9)	0.0667 (11)	0.0778 (12)	0.0099 (8)	−0.0039 (8)	−0.0028 (9)
C14	0.0493 (8)	0.0695 (11)	0.0501 (8)	0.0016 (7)	−0.0081 (7)	0.0007 (8)

Geometric parameters (Å, º)

Cl1—C3	1.7315 (16)	C9—C14	1.398 (2)
O1—C6	1.3817 (19)	C9—C10	1.388 (2)
O1—C7	1.3769 (19)	C10—C11	1.384 (2)
O2—C7	1.198 (2)	C11—C12	1.373 (2)
N1—C1	1.3914 (18)	C12—C13	1.373 (3)
N1—C7	1.3669 (19)	C13—C14	1.376 (3)
N1—C8	1.4711 (19)	C2—H2	0.9300
N2—C8	1.414 (2)	C4—H4	0.9300
N2—C9	1.3831 (19)	C5—H5	0.9300
N2—H2A	0.8600	C8—H8A	0.9700
C1—C2	1.3725 (19)	C8—H8B	0.9700
C1—C6	1.3818 (19)	C10—H10	0.9300
C2—C3	1.388 (2)	C11—H11	0.9300
C3—C4	1.376 (2)	C12—H12	0.9300
C4—C5	1.387 (2)	C13—H13	0.9300
C5—C6	1.368 (2)	C14—H14	0.9300
C6—O1—C7	107.78 (11)	C9—C10—C11	119.87 (14)
C1—N1—C7	109.19 (11)	C10—C11—C12	121.47 (16)
C1—N1—C8	125.75 (11)	C11—C12—C13	118.90 (17)
C7—N1—C8	124.99 (12)	C12—C13—C14	120.73 (17)
C8—N2—C9	124.23 (12)	C9—C14—C13	120.73 (15)
C9—N2—H2A	118.00	C1—C2—H2	122.00
C8—N2—H2A	118.00	C3—C2—H2	122.00
N1—C1—C6	106.29 (12)	C3—C4—H4	120.00
N1—C1—C2	132.05 (12)	C5—C4—H4	120.00
C2—C1—C6	121.65 (13)	C4—C5—H5	122.00
C1—C2—C3	115.20 (13)	C6—C5—H5	122.00
Cl1—C3—C4	118.73 (13)	N1—C8—H8A	109.00
Cl1—C3—C2	117.77 (12)	N1—C8—H8B	109.00
C2—C3—C4	123.49 (15)	N2—C8—H8A	109.00
C3—C4—C5	120.48 (15)	N2—C8—H8B	109.00
C4—C5—C6	116.25 (14)	H8A—C8—H8B	108.00
C1—C6—C5	122.93 (14)	C9—C10—H10	120.00
O1—C6—C5	128.24 (13)	C11—C10—H10	120.00
O1—C6—C1	108.83 (12)	C10—C11—H11	119.00
O1—C7—N1	107.90 (12)	C12—C11—H11	119.00
O1—C7—O2	122.84 (14)	C11—C12—H12	121.00
O2—C7—N1	129.27 (15)	C13—C12—H12	121.00
N1—C8—N2	113.63 (13)	C12—C13—H13	120.00
N2—C9—C10	122.83 (13)	C14—C13—H13	120.00
C10—C9—C14	118.29 (14)	C9—C14—H14	120.00
N2—C9—C14	118.87 (13)	C13—C14—H14	120.00
C7—O1—C6—C5	179.00 (16)	N1—C1—C2—C3	179.08 (15)
C6—O1—C7—O2	−178.94 (16)	C6—C1—C2—C3	−0.3 (2)
C7—O1—C6—C1	−0.57 (16)	N1—C1—C6—O1	0.04 (16)
C6—O1—C7—N1	0.88 (16)	C2—C1—C6—C5	0.0 (2)
C7—N1—C1—C2	−178.96 (16)	C1—C2—C3—Cl1	−179.79 (12)
C8—N1—C1—C2	3.9 (2)	C1—C2—C3—C4	0.2 (2)
C1—N1—C7—O1	−0.86 (16)	C2—C3—C4—C5	0.3 (3)
C8—N1—C7—O1	176.31 (13)	Cl1—C3—C4—C5	−179.75 (13)
C1—N1—C7—O2	178.93 (17)	C3—C4—C5—C6	−0.6 (2)
C8—N1—C7—O2	−3.9 (3)	C4—C5—C6—C1	0.5 (2)
C1—N1—C8—N2	−59.57 (18)	C4—C5—C6—O1	−179.03 (15)
C7—N1—C8—N2	123.72 (15)	N2—C9—C10—C11	−178.47 (15)
C8—N1—C1—C6	−176.64 (13)	C14—C9—C10—C11	0.6 (2)
C7—N1—C1—C6	0.51 (16)	N2—C9—C14—C13	179.13 (16)
C8—N2—C9—C10	−6.8 (2)	C10—C9—C14—C13	0.0 (2)
C9—N2—C8—N1	−72.99 (18)	C9—C10—C11—C12	−1.1 (3)
C8—N2—C9—C14	174.17 (15)	C10—C11—C12—C13	0.9 (3)
C2—C1—C6—O1	179.57 (13)	C11—C12—C13—C14	−0.3 (3)
N1—C1—C6—C5	−179.55 (14)	C12—C13—C14—C9	−0.2 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2A···O2^i	0.86	2.30	3.1296 (17)	162
C11—H11···Cl1^ii	0.93	2.70	3.5295 (17)	150

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