2-(1,3-Benzoxazol-2-yl)-1-phenyl­ethenyl benzoate

Mohammad Hassan Ghorbani

doi:10.1107/S1600536811036920

. 2011 Sep 30;67(Pt 10):o2723. doi: 10.1107/S1600536811036920

2-(1,3-Benzoxazol-2-yl)-1-phenylethenyl benzoate

Mohammad Hassan Ghorbani ^a,^*

PMCID: PMC3201545 PMID: 22065724

Abstract

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)—C_phenyl—C_phenyl and O_benzoxazole—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

C₂₂H₁₅NO₃
M _r = 341.35
Monoclinic,
a = 10.0152 (11) Å
b = 13.1911 (15) Å
c = 13.4430 (15) Å
β = 110.957 (2)°
V = 1658.5 (3) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 150 K
0.30 × 0.30 × 0.20 mm

Data collection

Bruker SMART 1K CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2007) ▶ T _min = 0.973, T _max = 0.982
10417 measured reflections
3254 independent reflections
2656 reflections with I > 2σ(I)
R _int = 0.021

Refinement

R[F ² > 2σ(F ²)] = 0.037
wR(F ²) = 0.093
S = 1.08
3254 reflections
236 parameters
H-atom parameters constrained
Δρ_max = 0.21 e Å⁻³
Δρ_min = −0.17 e Å⁻³

Data collection: SMART (Bruker, 2007 ▶); cell refinement: 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.

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536811036920/lh5319sup1.cif

e-67-o2723-sup1.cif^{(19.1KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811036920/lh5319Isup2.hkl

e-67-o2723-Isup2.hkl^{(159.7KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536811036920/lh5319Isup3.cml

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Acknowledgments

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.

supplementary crystallographic information

Comment

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).

Experimental

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.