4-{[(4Z)-5-Oxo-2-phenyl-4,5-dihydro-1,3-oxazol-4-yl­idene]meth­yl}phenyl acetate

Bharat B Baldaniya; Mukesh M Jotani; Edward R T Tiekink

doi:10.1107/S1600536810014911

. 2010 Apr 28;66(Pt 5):o1175. doi: 10.1107/S1600536810014911

4-{[(4Z)-5-Oxo-2-phenyl-4,5-dihydro-1,3-oxazol-4-ylidene]methyl}phenyl acetate

Bharat B Baldaniya ^a, Mukesh M Jotani ^b,^‡, Edward R T Tiekink ^c,^*

PMCID: PMC2979071 PMID: 21579216

Abstract

The title molecule, C₁₈H₁₃NO₄, shows a dihedral angle between the terminal acetyl group (r.m.s. deviation = 0.0081 Å) and remaining non-H atoms (r.m.s. = 0.0734 Å) of 53.45 (7)°. The configuration about the central olefinic bond is Z and overall the molecule has a U-shaped conformation. Supramolecular chains along the b-axis direction are found in the crystal structure. These are stabilized by (C=O)⋯π(ring centroid of the 1,3-oxazole ring) interactions [3.370 (2) Å].

Related literature

For background to the biological activity of 1,3-oxazole and imidazoles, see: Williams & Fu (2010 ▶); Khbnadidah et al. (2003 ▶). For related structures, see: Sun et al. (2007 ▶); Jotani & Baldaniya (2008 ▶).

Experimental

Crystal data

C₁₈H₁₃NO₄
M _r = 307.29
Monoclinic,
a = 13.3507 (15) Å
b = 3.9443 (9) Å
c = 28.527 (5) Å
β = 98.025 (11)°
V = 1487.5 (5) Å³
Z = 4
Cu Kα radiation
μ = 0.81 mm⁻¹
T = 293 K
0.40 × 0.20 × 0.15 mm

Data collection

Enraf–Nonius CAD-4 diffractometer
Absorption correction: ψ scan (North et al., 1968 ▶) T _min = 0.852, T _max = 0.997
2593 measured reflections
2491 independent reflections
1795 reflections with I > 2σ(I)
R _int = 0.054
2 standard reflections every 3600 min intensity decay: none

Refinement

R[F ² > 2σ(F ²)] = 0.050
wR(F ²) = 0.140
S = 1.06
2491 reflections
210 parameters
H-atom parameters constrained
Δρ_max = 0.23 e Å⁻³
Δρ_min = −0.23 e Å⁻³

Data collection: XCAD4 (Harms & Wocadlo, 1996 ▶); cell refinement: XCAD4; data reduction: XCAD4; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶) and DIAMOND (Brandenburg, 2006 ▶); software used to prepare material for publication: publCIF (Westrip, 2010 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810014911/lh5032sup1.cif

e-66-o1175-sup1.cif^{(16.6KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810014911/lh5032Isup2.hkl

e-66-o1175-Isup2.hkl^{(119.9KB, hkl)}

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

Acknowledgments

The authors are thankful to the Department of Science and Technology (DST), and the SAIF, I.I.T. Madras, Chennai, India, for the X-ray data collection. MMJ is grateful to the University Grant Commission (Western Regional Office), India, for a Minor Research Project F. No.47-254/07.

supplementary crystallographic information

Comment

The 1,3-oxazole ring is known to have biological activity in its own right (Williams & Fu, 2010) and serves as a useful synthetic intermediate for the synthesis of imidazoles that are also possess a wide spectrum of biological activities, such as herbicides, fungicides, anti-bacterials, etc. (Khbnadidah et al., 2003). In continuation of structural studies of oxazole compounds (Jotani & Baldaniya, 2008), the crystal structure of title compound, (I), is described herein.

The molecule of (I) is twisted around the C3–O2 bond as seen in the C2–O2–C3–C4 torsion angle of 58.2 (3) °. This results in a dihedral angle of 53.45 (7) ° between the acetyl residue [r.m.s. deviation = 0.0081 Å] and the remaining non-hydrogen atoms [r.m.s. = 0.0734 Å]; the dihedral angle formed between the two benzene rings is 5.10 (12) °. The configuration about the C9═C10 bond [1.343 (3) Å] is Z, and as the two benzene rings are orientated to the same side of the molecule, the overall molecular conformation is U-shaped. A similar conformation was reported in a di-methoxy derivative of (I), namely 2,6-dimethoxy-4-(5-oxo-2-phenyl-4,5-dihydro-1,3-oxazol-4-ylidenemethyl)- phenyl acetate (Sun et al., 2007).

The crystal packing is dominated by (C═O)···π interactions that connect molecules into a linear supramolecular chain along the b axis, Fig. 2. The parameters defining this interaction are C11═O3···ring centroid(1,3-oxazole ring)ⁱ = 3.370 (2) Å and angle = 85.11 (14) ° for i: x, 1+y, z.

Experimental

A mixture of 4-acetoxyoxy benzaldehyde (0.25 mol), benzoyl amino acetic acid (0.25 mol), acetyl acetate (0.30 mol) and anhydrous sodium acetate (0.25 mol) were taken in a 500 ml round bottom flask and heated on an electric hot plate with constant stirring. After the complete liquefaction of the mixture, the flask was transferred to a sand bath and further heated for 2.5 h. Ethanol (100 ml) was added slowly to the flask and the mixture was allowed to stand overnight. The crystalline product obtained was filtered with ice-cold alcohol and then with boiling water. The crude product was crystallised from ethanol (95%) to obtain the final product (78% yield; m.pt. 428 K). The colourless crystals were obtained by slow evaporation from an ethanol solution of (I).