organic compounds
2-(1,3-Benzoxazol-2-yl)-1-phenylethenyl benzoate
aFalavarjan Branch, Islamic Azad University, Falavarjan, Isfahan, Iran
*Correspondence e-mail: ghorbani@iaufala.ac.ir, moha_ghorbani@yahoo.com
In the title molecule, C22H15NO3, the configuration about the ethylenic double bond is Z configuration and it is approximately coplanar with the adjacent phenyl ring and benzoxazole ring system as indicated by the C(H)=C(O)—Cphenyl—Cphenyl and Obenzoxazole—C—C(H)=C(O) torsion angles of 179.88 (15) and 5.7 (2)°, respectively. The dihedral angle between the essentially planar (r.m.s. deviation = 0.080 Å) 2-(1,3-benzoxazol-2-yl)-1-phenylethenyl group and the benzoate phenyl ring is 61.51 (6)°. A short intramolecular O⋯O non-bonded interaction of 2.651 (2) Å is present.
Related literature
For background and synthetic details, see: Ciurdaru & Ciuciu (1979); Zhou & Pittman (2004). For related structures, see: Markham et al. (1999); Punte et al. (1990); Loghmani et al. (2007). For van der Waals radii, see: Bondi (1964).
Experimental
Crystal data
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Data collection: SMART (Bruker, 2007); cell SAINT (Bruker, 2007); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL; molecular graphics: Mercury (Macrae et al., 2006); software used to prepare material for publication: SHELXTL.
Supporting information
https://doi.org/10.1107/S1600536811036920/lh5319sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536811036920/lh5319Isup2.hkl
Supporting information file. DOI: https://doi.org/10.1107/S1600536811036920/lh5319Isup3.cml
The title compound was prepared as in the literature (Ciurdaru & Ciuciu, 1979), except that benzoyl chloride and triethylamine (both 30 mmol) were used to complete the reaction. Suitable single crystals for X-ray analysis were obtained from an ethanol solution of the title compound at room temperature.
All H-atoms were positioned geometrically and refined using a riding model with C—H distances = 0.95 Å (both aryl and vinyl-H) and isotropic displacement parameters for these atoms were Uiso(H) = 1.2Ueq(C).
The reaction of 2-methylbenzoxazole (A) (Fig. 1) with acyl chlorides such as benzoyl chloride was carried out for the first time by Ciurdaru and Ciuciu (1979), who used the same conditions for reactions of other 2-methylbenzoazoles with acyl chlorides. After infra red and mass spectral investigations and elemental analysis of acylated derivatives, it was suggested that the double acylated structure of (C) was the product of these reactions. This structure differs with the double acylated structure of (D) for the product of acylation of some azoles such as 2-methylthiazoles (Zhou & Pittman, 2004), although these reactions have been done under the same conditions. In fact, based on the presented data, not only the enolester (C) but also the conjugated ketone (D) can be considered as product of the reactions of 2-methylbenzoazoles with acyl chlorides. In addition to the molecular structure, the configuration of the ethylenic double bond in both probable structures was also questionable. In order to clarify these ambiguous situations, the
determination of the title compound was carried out.The molecular structure of the title compound is shown in Fig. 2. The enolester structure is confirmed as product of the reaction and the ethylenic double bond (C8═C9) has a Z configuration. The ethylenic double bond is co-planar with the connected phenyl ring (the torsion angle of C8—C9—C10—C15 is 179.88 (15)°) and also is approximately co-planar with the planar benzoxazole rings (the torsion angles of O1—C7—C8—C9 and N—C7—C8—C9 are equal to 5.7 (2)° and -174.08 (15)°, respectively). On the other hand, the benzoyl moiety is stituated out of the plane of co-planar components (the torsion angles of C16—O2—C9—C8 and C16—O2—C9—C10 are -89.17 (16) and 95.31 (14), respectively).
The C8—C9 bond length (1.335 (2) Å) in the structure is within the normal range of an unconjugated ethylenic double bond. Also, due to the more resonance interaction of nonbonding electrons on the O2 with the π system of C=O relative to C=C, the O2—C16 bond length (1.3641 (17) Å) is shorter than O2—C9 (1.4010 (16) Å). These values may indicate that the π system of ethylenic double bond is not fully delocalized.
An intramolecular O1···O2 non-bonded distance (2.651 (2) Å) is shorter than the sum of the corresponding van der Waals radii (3.04 Å) (Bondi, 1964). This phenomenon is similar to the intramolecular non-bonded interactions between an oxygen atom and atoms of group VIA in the periodic table (S, Se and Te) (Markham et al., 1999) and shows that an attractive non-bonded interaction between O1 and O2 must be present in the molecule (Punte et al., 1990). This attraction may be responsible for the Z configuration becoming the preferred configuration for the ethylenic double bond (Loghmani et al., 2007).
For background and synthetic details, see: Ciurdaru & Ciuciu (1979); Zhou & Pittman (2004). For related structures, see: Markham et al. (1999); Punte et al. (1990); Loghmani et al. (2007). For van der Waals radii, see: Bondi (1964).
Data collection: SMART (Bruker, 2007); cell
SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: Mercury (Macrae et al., 2006); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).C22H15NO3 | F(000) = 712 |
Mr = 341.35 | Dx = 1.367 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yn | Cell parameters from 6385 reflections |
a = 10.0152 (11) Å | θ = 2.2–28.2° |
b = 13.1911 (15) Å | µ = 0.09 mm−1 |
c = 13.4430 (15) Å | T = 150 K |
β = 110.957 (2)° | Block, colourless |
V = 1658.5 (3) Å3 | 0.30 × 0.30 × 0.20 mm |
Z = 4 |
Bruker SMART 1K CCD diffractometer | 3254 independent reflections |
Radiation source: sealed tube | 2656 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.021 |
thin–slice ω scans | θmax = 26.0°, θmin = 2.2° |
Absorption correction: multi-scan (SADABS; Bruker, 2007) | h = −12→12 |
Tmin = 0.973, Tmax = 0.982 | k = −16→16 |
10417 measured reflections | l = −14→16 |
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)] = 0.037 | H-atom parameters constrained |
wR(F2) = 0.093 | w = 1/[σ2(Fo2) + (0.034P)2 + 0.6798P] where P = (Fo2 + 2Fc2)/3 |
S = 1.08 | (Δ/σ)max < 0.001 |
3254 reflections | Δρmax = 0.21 e Å−3 |
236 parameters | Δρmin = −0.17 e Å−3 |
0 restraints | Extinction correction: SHELXTL (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.0063 (8) |
C22H15NO3 | V = 1658.5 (3) Å3 |
Mr = 341.35 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 10.0152 (11) Å | µ = 0.09 mm−1 |
b = 13.1911 (15) Å | T = 150 K |
c = 13.4430 (15) Å | 0.30 × 0.30 × 0.20 mm |
β = 110.957 (2)° |
Bruker SMART 1K CCD diffractometer | 3254 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2007) | 2656 reflections with I > 2σ(I) |
Tmin = 0.973, Tmax = 0.982 | Rint = 0.021 |
10417 measured reflections |
R[F2 > 2σ(F2)] = 0.037 | 0 restraints |
wR(F2) = 0.093 | H-atom parameters constrained |
S = 1.08 | Δρmax = 0.21 e Å−3 |
3254 reflections | Δρmin = −0.17 e Å−3 |
236 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
O1 | 0.52934 (10) | 0.29679 (7) | 0.67880 (8) | 0.0276 (2) | |
O2 | 0.67141 (10) | 0.39020 (7) | 0.57269 (8) | 0.0242 (2) | |
O3 | 0.87424 (12) | 0.36358 (9) | 0.71372 (9) | 0.0385 (3) | |
N | 0.40724 (13) | 0.39634 (9) | 0.75280 (10) | 0.0275 (3) | |
C1 | 0.44901 (15) | 0.23434 (11) | 0.71744 (11) | 0.0256 (3) | |
C2 | 0.44378 (17) | 0.12991 (11) | 0.71550 (13) | 0.0330 (4) | |
H2A | 0.4990 | 0.0902 | 0.6855 | 0.040* | |
C3 | 0.35225 (17) | 0.08696 (13) | 0.76035 (14) | 0.0386 (4) | |
H3A | 0.3434 | 0.0153 | 0.7609 | 0.046* | |
C4 | 0.27291 (17) | 0.14641 (14) | 0.80472 (14) | 0.0397 (4) | |
H4A | 0.2107 | 0.1140 | 0.8341 | 0.048* | |
C5 | 0.28183 (16) | 0.25104 (13) | 0.80738 (13) | 0.0353 (4) | |
H5A | 0.2282 | 0.2910 | 0.8385 | 0.042* | |
C6 | 0.37305 (15) | 0.29498 (11) | 0.76227 (12) | 0.0266 (3) | |
C7 | 0.49753 (15) | 0.39237 (11) | 0.70353 (12) | 0.0260 (3) | |
C8 | 0.56266 (15) | 0.47952 (11) | 0.67458 (12) | 0.0266 (3) | |
H8A | 0.5435 | 0.5432 | 0.6997 | 0.032* | |
C9 | 0.64666 (14) | 0.48137 (10) | 0.61670 (11) | 0.0239 (3) | |
C10 | 0.70965 (14) | 0.57141 (11) | 0.58589 (11) | 0.0242 (3) | |
C11 | 0.68438 (15) | 0.66894 (11) | 0.61587 (12) | 0.0274 (3) | |
H11A | 0.6263 | 0.6778 | 0.6577 | 0.033* | |
C12 | 0.74315 (16) | 0.75261 (11) | 0.58514 (13) | 0.0315 (4) | |
H12A | 0.7244 | 0.8185 | 0.6055 | 0.038* | |
C13 | 0.82906 (16) | 0.74112 (12) | 0.52499 (13) | 0.0331 (4) | |
H13A | 0.8697 | 0.7988 | 0.5044 | 0.040* | |
C14 | 0.85531 (17) | 0.64518 (12) | 0.49504 (13) | 0.0328 (4) | |
H14A | 0.9143 | 0.6369 | 0.4538 | 0.039* | |
C15 | 0.79595 (16) | 0.56091 (11) | 0.52499 (12) | 0.0288 (3) | |
H15A | 0.8143 | 0.4953 | 0.5038 | 0.035* | |
C16 | 0.78482 (15) | 0.33301 (11) | 0.63327 (12) | 0.0251 (3) | |
C17 | 0.78117 (15) | 0.23113 (11) | 0.58611 (11) | 0.0246 (3) | |
C18 | 0.90826 (17) | 0.17707 (12) | 0.61258 (13) | 0.0313 (3) | |
H18A | 0.9954 | 0.2064 | 0.6581 | 0.038* | |
C19 | 0.90733 (19) | 0.08035 (13) | 0.57236 (14) | 0.0392 (4) | |
H19A | 0.9942 | 0.0435 | 0.5895 | 0.047* | |
C20 | 0.7804 (2) | 0.03741 (12) | 0.50741 (14) | 0.0413 (4) | |
H20A | 0.7801 | −0.0292 | 0.4805 | 0.050* | |
C21 | 0.65337 (19) | 0.09079 (12) | 0.48128 (14) | 0.0382 (4) | |
H21A | 0.5663 | 0.0608 | 0.4365 | 0.046* | |
C22 | 0.65338 (16) | 0.18795 (11) | 0.52046 (12) | 0.0292 (3) | |
H22A | 0.5665 | 0.2249 | 0.5026 | 0.035* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0315 (5) | 0.0228 (5) | 0.0324 (6) | −0.0026 (4) | 0.0162 (5) | −0.0022 (4) |
O2 | 0.0245 (5) | 0.0210 (5) | 0.0272 (5) | 0.0009 (4) | 0.0092 (4) | −0.0023 (4) |
O3 | 0.0312 (6) | 0.0364 (6) | 0.0385 (7) | 0.0019 (5) | 0.0013 (5) | −0.0067 (5) |
N | 0.0280 (6) | 0.0262 (6) | 0.0315 (7) | −0.0010 (5) | 0.0145 (6) | −0.0030 (5) |
C1 | 0.0240 (7) | 0.0286 (8) | 0.0224 (7) | −0.0049 (6) | 0.0061 (6) | −0.0003 (6) |
C2 | 0.0375 (8) | 0.0263 (8) | 0.0321 (8) | −0.0049 (7) | 0.0088 (7) | −0.0029 (7) |
C3 | 0.0376 (9) | 0.0310 (8) | 0.0394 (10) | −0.0105 (7) | 0.0041 (7) | 0.0052 (7) |
C4 | 0.0296 (8) | 0.0492 (10) | 0.0369 (9) | −0.0125 (7) | 0.0077 (7) | 0.0110 (8) |
C5 | 0.0283 (8) | 0.0477 (10) | 0.0320 (9) | −0.0034 (7) | 0.0131 (7) | 0.0026 (7) |
C6 | 0.0237 (7) | 0.0299 (8) | 0.0240 (7) | −0.0015 (6) | 0.0058 (6) | −0.0005 (6) |
C7 | 0.0266 (7) | 0.0232 (7) | 0.0280 (8) | 0.0001 (6) | 0.0096 (6) | −0.0021 (6) |
C8 | 0.0284 (7) | 0.0206 (7) | 0.0313 (8) | −0.0004 (6) | 0.0116 (6) | −0.0031 (6) |
C9 | 0.0231 (7) | 0.0208 (7) | 0.0256 (8) | 0.0009 (5) | 0.0059 (6) | −0.0030 (6) |
C10 | 0.0206 (6) | 0.0247 (7) | 0.0234 (7) | −0.0003 (6) | 0.0032 (6) | 0.0003 (6) |
C11 | 0.0255 (7) | 0.0255 (7) | 0.0297 (8) | 0.0004 (6) | 0.0082 (6) | −0.0002 (6) |
C12 | 0.0312 (8) | 0.0220 (7) | 0.0354 (9) | −0.0007 (6) | 0.0049 (7) | 0.0018 (6) |
C13 | 0.0303 (8) | 0.0303 (8) | 0.0344 (9) | −0.0050 (6) | 0.0062 (7) | 0.0085 (7) |
C14 | 0.0308 (8) | 0.0372 (9) | 0.0322 (9) | −0.0013 (7) | 0.0134 (7) | 0.0039 (7) |
C15 | 0.0301 (8) | 0.0258 (7) | 0.0303 (8) | −0.0007 (6) | 0.0107 (6) | −0.0009 (6) |
C16 | 0.0227 (7) | 0.0265 (7) | 0.0284 (8) | 0.0000 (6) | 0.0119 (6) | 0.0018 (6) |
C17 | 0.0286 (7) | 0.0236 (7) | 0.0256 (8) | 0.0028 (6) | 0.0147 (6) | 0.0033 (6) |
C18 | 0.0321 (8) | 0.0341 (8) | 0.0300 (8) | 0.0080 (7) | 0.0139 (7) | 0.0062 (7) |
C19 | 0.0500 (10) | 0.0355 (9) | 0.0383 (10) | 0.0206 (8) | 0.0236 (8) | 0.0109 (8) |
C20 | 0.0667 (12) | 0.0214 (7) | 0.0448 (10) | 0.0061 (8) | 0.0312 (9) | 0.0011 (7) |
C21 | 0.0468 (10) | 0.0288 (8) | 0.0433 (10) | −0.0056 (7) | 0.0215 (8) | −0.0072 (7) |
C22 | 0.0313 (8) | 0.0251 (7) | 0.0346 (9) | 0.0002 (6) | 0.0159 (7) | −0.0021 (6) |
O1—C1 | 1.3764 (17) | C10—C15 | 1.394 (2) |
O1—C7 | 1.3703 (17) | C11—H11A | 0.9500 |
O2—C9 | 1.4010 (16) | C11—C12 | 1.382 (2) |
O2—C16 | 1.3641 (17) | C12—H12A | 0.9500 |
O3—C16 | 1.2006 (18) | C12—C13 | 1.384 (2) |
N—C6 | 1.3973 (19) | C13—H13A | 0.9500 |
N—C7 | 1.2990 (18) | C13—C14 | 1.381 (2) |
C1—C2 | 1.378 (2) | C14—H14A | 0.9500 |
C1—C6 | 1.382 (2) | C14—C15 | 1.387 (2) |
C2—H2A | 0.9500 | C15—H15A | 0.9500 |
C2—C3 | 1.386 (2) | C16—C17 | 1.481 (2) |
C3—H3A | 0.9500 | C17—C18 | 1.390 (2) |
C3—C4 | 1.393 (3) | C17—C22 | 1.390 (2) |
C4—H4A | 0.9500 | C18—H18A | 0.9500 |
C4—C5 | 1.383 (2) | C18—C19 | 1.384 (2) |
C5—H5A | 0.9500 | C19—H19A | 0.9500 |
C5—C6 | 1.391 (2) | C19—C20 | 1.380 (3) |
C7—C8 | 1.442 (2) | C20—H20A | 0.9500 |
C8—H8A | 0.9500 | C20—C21 | 1.385 (2) |
C8—C9 | 1.335 (2) | C21—H21A | 0.9500 |
C9—C10 | 1.472 (2) | C21—C22 | 1.386 (2) |
C10—C11 | 1.398 (2) | C22—H22A | 0.9500 |
C1—O1—C7 | 103.96 (11) | H11A—C11—C12 | 119.7 |
C9—O2—C16 | 117.25 (11) | C11—C12—H12A | 119.7 |
C6—N—C7 | 104.24 (12) | C11—C12—C13 | 120.51 (14) |
O1—C1—C2 | 127.91 (14) | H12A—C12—C13 | 119.7 |
O1—C1—C6 | 107.78 (12) | C12—C13—H13A | 120.2 |
C2—C1—C6 | 124.30 (14) | C12—C13—C14 | 119.58 (14) |
C1—C2—H2A | 122.4 | H13A—C13—C14 | 120.2 |
C1—C2—C3 | 115.27 (15) | C13—C14—H14A | 119.9 |
H2A—C2—C3 | 122.4 | C13—C14—C15 | 120.25 (15) |
C2—C3—H3A | 119.2 | H14A—C14—C15 | 119.9 |
C2—C3—C4 | 121.57 (15) | C10—C15—C14 | 120.75 (14) |
H3A—C3—C4 | 119.2 | C10—C15—H15A | 119.6 |
C3—C4—H4A | 118.9 | C14—C15—H15A | 119.6 |
C3—C4—C5 | 122.10 (15) | O2—C16—O3 | 123.06 (13) |
H4A—C4—C5 | 118.9 | O2—C16—C17 | 111.01 (12) |
C4—C5—H5A | 121.6 | O3—C16—C17 | 125.93 (13) |
C4—C5—C6 | 116.82 (15) | C16—C17—C18 | 118.42 (14) |
H5A—C5—C6 | 121.6 | C16—C17—C22 | 121.31 (13) |
N—C6—C1 | 108.85 (12) | C18—C17—C22 | 120.21 (14) |
N—C6—C5 | 131.23 (14) | C17—C18—H18A | 120.2 |
C1—C6—C5 | 119.92 (14) | C17—C18—C19 | 119.68 (16) |
O1—C7—N | 115.18 (12) | H18A—C18—C19 | 120.2 |
O1—C7—C8 | 120.07 (12) | C18—C19—H19A | 120.0 |
N—C7—C8 | 124.75 (13) | C18—C19—C20 | 120.08 (15) |
C7—C8—H8A | 116.1 | H19A—C19—C20 | 120.0 |
C7—C8—C9 | 127.73 (14) | C19—C20—H20A | 119.8 |
H8A—C8—C9 | 116.1 | C19—C20—C21 | 120.43 (15) |
O2—C9—C8 | 118.30 (12) | H20A—C20—C21 | 119.8 |
O2—C9—C10 | 114.55 (12) | C20—C21—H21A | 120.0 |
C8—C9—C10 | 126.98 (13) | C20—C21—C22 | 119.92 (16) |
C9—C10—C11 | 121.43 (13) | H21A—C21—C22 | 120.0 |
C9—C10—C15 | 120.22 (13) | C17—C22—C21 | 119.67 (14) |
C11—C10—C15 | 118.35 (13) | C17—C22—H22A | 120.2 |
C10—C11—H11A | 119.7 | C21—C22—H22A | 120.2 |
C10—C11—C12 | 120.57 (14) | ||
C7—O1—C1—C2 | −178.43 (15) | O2—C9—C10—C15 | −5.06 (19) |
C7—O1—C1—C6 | 0.41 (15) | C8—C9—C10—C11 | −0.5 (2) |
O1—C1—C2—C3 | −179.83 (14) | C8—C9—C10—C15 | 179.88 (15) |
C6—C1—C2—C3 | 1.5 (2) | C9—C10—C11—C12 | −179.26 (13) |
C1—C2—C3—C4 | −0.5 (2) | C15—C10—C11—C12 | 0.4 (2) |
C2—C3—C4—C5 | −0.6 (3) | C10—C11—C12—C13 | −0.6 (2) |
C3—C4—C5—C6 | 0.7 (2) | C11—C12—C13—C14 | 0.4 (2) |
O1—C1—C6—N | −0.68 (16) | C12—C13—C14—C15 | 0.0 (2) |
O1—C1—C6—C5 | 179.74 (13) | C13—C14—C15—C10 | −0.3 (2) |
C2—C1—C6—N | 178.21 (14) | C9—C10—C15—C14 | 179.68 (14) |
C2—C1—C6—C5 | −1.4 (2) | C11—C10—C15—C14 | 0.1 (2) |
C4—C5—C6—N | −179.30 (15) | C9—O2—C16—O3 | −11.2 (2) |
C4—C5—C6—C1 | 0.2 (2) | C9—O2—C16—C17 | 169.02 (11) |
C7—N—C6—C1 | 0.66 (16) | O2—C16—C17—C18 | 157.19 (13) |
C7—N—C6—C5 | −179.81 (16) | O2—C16—C17—C22 | −25.54 (18) |
C6—N—C7—O1 | −0.42 (17) | O3—C16—C17—C18 | −22.6 (2) |
C6—N—C7—C8 | 179.39 (14) | O3—C16—C17—C22 | 154.63 (15) |
C1—O1—C7—N | 0.01 (16) | C16—C17—C18—C19 | 177.96 (14) |
C1—O1—C7—C8 | −179.80 (13) | C22—C17—C18—C19 | 0.7 (2) |
O1—C7—C8—C9 | 5.7 (2) | C17—C18—C19—C20 | −0.8 (2) |
N—C7—C8—C9 | −174.08 (15) | C18—C19—C20—C21 | 0.5 (3) |
C7—C8—C9—O2 | 3.6 (2) | C19—C20—C21—C22 | 0.0 (3) |
C7—C8—C9—C10 | 178.51 (14) | C20—C21—C22—C17 | −0.2 (2) |
C16—O2—C9—C8 | −89.17 (16) | C16—C17—C22—C21 | −177.38 (14) |
C16—O2—C9—C10 | 95.31 (14) | C18—C17—C22—C21 | −0.2 (2) |
O2—C9—C10—C11 | 174.55 (12) |
Experimental details
Crystal data | |
Chemical formula | C22H15NO3 |
Mr | 341.35 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 150 |
a, b, c (Å) | 10.0152 (11), 13.1911 (15), 13.4430 (15) |
β (°) | 110.957 (2) |
V (Å3) | 1658.5 (3) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.09 |
Crystal size (mm) | 0.30 × 0.30 × 0.20 |
Data collection | |
Diffractometer | Bruker SMART 1K CCD |
Absorption correction | Multi-scan (SADABS; Bruker, 2007) |
Tmin, Tmax | 0.973, 0.982 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 10417, 3254, 2656 |
Rint | 0.021 |
(sin θ/λ)max (Å−1) | 0.617 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.037, 0.093, 1.08 |
No. of reflections | 3254 |
No. of parameters | 236 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.21, −0.17 |
Computer programs: SMART (Bruker, 2007), SAINT (Bruker, 2007), SHELXTL (Sheldrick, 2008), Mercury (Macrae et al., 2006).
Acknowledgements
The author thanks the Islamic Azad University-Falavarjan Branch for financial support. He also wishes to thank Professor M. H. Habibi, University of Isfahan, and Dr M. Pourayoubi, Ferdowsi University of Mashhad, for their helpful assistance.
References
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This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
The reaction of 2-methylbenzoxazole (A) (Fig. 1) with acyl chlorides such as benzoyl chloride was carried out for the first time by Ciurdaru and Ciuciu (1979), who used the same conditions for reactions of other 2-methylbenzoazoles with acyl chlorides. After infra red and mass spectral investigations and elemental analysis of acylated derivatives, it was suggested that the double acylated structure of (C) was the product of these reactions. This structure differs with the double acylated structure of (D) for the product of acylation of some azoles such as 2-methylthiazoles (Zhou & Pittman, 2004), although these reactions have been done under the same conditions. In fact, based on the presented data, not only the enolester (C) but also the conjugated ketone (D) can be considered as product of the reactions of 2-methylbenzoazoles with acyl chlorides. In addition to the molecular structure, the configuration of the ethylenic double bond in both probable structures was also questionable. In order to clarify these ambiguous situations, the crystal structure determination of the title compound was carried out.
The molecular structure of the title compound is shown in Fig. 2. The enolester structure is confirmed as product of the reaction and the ethylenic double bond (C8═C9) has a Z configuration. The ethylenic double bond is co-planar with the connected phenyl ring (the torsion angle of C8—C9—C10—C15 is 179.88 (15)°) and also is approximately co-planar with the planar benzoxazole rings (the torsion angles of O1—C7—C8—C9 and N—C7—C8—C9 are equal to 5.7 (2)° and -174.08 (15)°, respectively). On the other hand, the benzoyl moiety is stituated out of the plane of co-planar components (the torsion angles of C16—O2—C9—C8 and C16—O2—C9—C10 are -89.17 (16) and 95.31 (14), respectively).
The C8—C9 bond length (1.335 (2) Å) in the structure is within the normal range of an unconjugated ethylenic double bond. Also, due to the more resonance interaction of nonbonding electrons on the O2 with the π system of C=O relative to C=C, the O2—C16 bond length (1.3641 (17) Å) is shorter than O2—C9 (1.4010 (16) Å). These values may indicate that the π system of ethylenic double bond is not fully delocalized.
An intramolecular O1···O2 non-bonded distance (2.651 (2) Å) is shorter than the sum of the corresponding van der Waals radii (3.04 Å) (Bondi, 1964). This phenomenon is similar to the intramolecular non-bonded interactions between an oxygen atom and atoms of group VIA in the periodic table (S, Se and Te) (Markham et al., 1999) and shows that an attractive non-bonded interaction between O1 and O2 must be present in the molecule (Punte et al., 1990). This attraction may be responsible for the Z configuration becoming the preferred configuration for the ethylenic double bond (Loghmani et al., 2007).