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Acta Crystallogr Sect E Struct Rep Online. 2010 May 1; 66(Pt 5): o1175.
Published online 2010 April 28. doi:  10.1107/S1600536810014911
PMCID: PMC2979071

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

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 [triangle]); Khbnadidah et al. (2003 [triangle]). For related structures, see: Sun et al. (2007 [triangle]); Jotani & Baldaniya (2008 [triangle]).

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Object name is e-66-o1175-scheme1.jpg

Experimental

Crystal data

  • C18H13NO4
  • M r = 307.29
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-66-o1175-efi1.jpg
  • 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 [triangle]) 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
  • Δρmax = 0.23 e Å−3
  • Δρmin = −0.23 e Å−3

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

Supplementary Material

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

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

Refinement

The H atoms were geometrically placed (C–H = 0.93–0.96 Å) and refined as riding with Uiso(H) = 1.2–1.5Ueq(C).

Figures

Fig. 1.
The molecular structure of (I) showing the atom-labelling scheme and displacement ellipsoids at the 35% probability level.
Fig. 2.
A supramolecular chain aligned along the b axis in (I), mediated by (C═ O)···π interactions (purple dashed lines). Colour code: O, red; N, blue; C, grey; and H, green.

Crystal data

C18H13NO4F(000) = 640
Mr = 307.29Dx = 1.372 Mg m3
Monoclinic, P21/cCu Kα radiation, λ = 1.54180 Å
Hall symbol: -P 2ybcCell parameters from 25 reflections
a = 13.3507 (15) Åθ = 20.0–30.0°
b = 3.9443 (9) ŵ = 0.81 mm1
c = 28.527 (5) ÅT = 293 K
β = 98.025 (11)°Block, colourless
V = 1487.5 (5) Å30.40 × 0.20 × 0.15 mm
Z = 4

Data collection

Enraf–Nonius CAD-4 diffractometer1795 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.054
graphiteθmax = 64.9°, θmin = 3.1°
2θ scanh = 0→15
Absorption correction: ψ scan (North et al., 1968)k = 0→4
Tmin = 0.852, Tmax = 0.997l = −33→33
2593 measured reflections2 standard reflections every 3600 min
2491 independent reflections intensity decay: none

Refinement

Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.050H-atom parameters constrained
wR(F2) = 0.140w = 1/[σ2(Fo2) + (0.0834P)2 + 0.1813P] where P = (Fo2 + 2Fc2)/3
S = 1.06(Δ/σ)max < 0.001
2491 reflectionsΔρmax = 0.23 e Å3
210 parametersΔρmin = −0.23 e Å3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0081 (8)

Special details

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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 (Å2)

xyzUiso*/Ueq
O10.98210 (13)−0.0744 (6)0.36427 (7)0.0805 (7)
O20.96858 (10)−0.3277 (4)0.43327 (5)0.0501 (4)
O30.36614 (12)0.4187 (5)0.44993 (6)0.0606 (5)
O40.32332 (10)0.1834 (4)0.37774 (5)0.0466 (4)
N10.47109 (13)−0.0534 (5)0.36494 (6)0.0430 (5)
C11.12156 (18)−0.3904 (7)0.40327 (10)0.0628 (7)
H1A1.1314−0.52500.37630.094*
H1B1.1304−0.52970.43110.094*
H1C1.1700−0.20910.40690.094*
C21.01799 (17)−0.2475 (7)0.39635 (9)0.0496 (6)
C30.86835 (15)−0.2184 (6)0.43289 (8)0.0425 (5)
C40.79303 (16)−0.3064 (6)0.39696 (8)0.0447 (6)
H40.8082−0.43180.37130.054*
C50.69517 (15)−0.2074 (6)0.39935 (7)0.0414 (5)
H50.6442−0.26600.37510.050*
C60.67139 (15)−0.0187 (6)0.43805 (7)0.0388 (5)
C70.74930 (16)0.0581 (6)0.47402 (8)0.0453 (6)
H70.73480.17870.50030.054*
C80.84763 (16)−0.0399 (6)0.47180 (7)0.0479 (6)
H80.89900.01380.49620.057*
C90.57088 (15)0.1106 (6)0.44158 (7)0.0406 (5)
H90.56400.21870.46990.049*
C100.48645 (15)0.0971 (6)0.40999 (7)0.0396 (5)
C110.39108 (16)0.2560 (6)0.41824 (8)0.0435 (5)
C120.37851 (15)0.0018 (6)0.34861 (7)0.0410 (5)
C130.32449 (17)−0.1052 (6)0.30296 (8)0.0449 (6)
C140.22131 (19)−0.0575 (7)0.29152 (9)0.0566 (7)
H140.18490.04840.31290.068*
C150.1725 (2)−0.1672 (8)0.24835 (10)0.0686 (8)
H150.1030−0.13810.24090.082*
C160.2258 (2)−0.3186 (7)0.21650 (9)0.0692 (8)
H160.1924−0.39290.18750.083*
C170.3283 (2)−0.3612 (7)0.22719 (9)0.0673 (8)
H170.3644−0.46030.20510.081*
C180.3783 (2)−0.2584 (7)0.27036 (8)0.0567 (7)
H180.4477−0.29130.27770.068*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
O10.0539 (11)0.1108 (18)0.0780 (13)0.0078 (11)0.0130 (9)0.0395 (13)
O20.0390 (8)0.0609 (11)0.0510 (9)0.0101 (7)0.0086 (7)0.0066 (8)
O30.0503 (10)0.0774 (13)0.0557 (10)0.0091 (9)0.0136 (8)−0.0205 (10)
O40.0387 (8)0.0522 (10)0.0487 (9)0.0046 (7)0.0056 (6)−0.0073 (8)
N10.0432 (10)0.0431 (11)0.0428 (10)0.0031 (9)0.0060 (8)−0.0049 (9)
C10.0478 (14)0.0644 (18)0.0793 (17)0.0082 (13)0.0195 (12)−0.0008 (15)
C20.0418 (12)0.0538 (16)0.0533 (13)−0.0003 (11)0.0075 (10)−0.0007 (12)
C30.0369 (11)0.0450 (13)0.0460 (12)0.0036 (10)0.0069 (9)0.0089 (11)
C40.0455 (12)0.0452 (14)0.0442 (12)0.0020 (11)0.0088 (9)−0.0014 (11)
C50.0412 (11)0.0422 (13)0.0401 (11)−0.0019 (10)0.0034 (9)−0.0006 (10)
C60.0407 (11)0.0385 (13)0.0380 (10)−0.0005 (9)0.0085 (9)0.0045 (10)
C70.0442 (12)0.0521 (14)0.0400 (11)0.0002 (11)0.0070 (9)−0.0052 (11)
C80.0397 (12)0.0605 (16)0.0423 (12)−0.0009 (11)0.0017 (9)−0.0023 (11)
C90.0419 (11)0.0411 (13)0.0400 (11)−0.0015 (10)0.0096 (9)−0.0022 (10)
C100.0402 (11)0.0386 (13)0.0410 (11)0.0010 (10)0.0088 (9)−0.0017 (10)
C110.0410 (11)0.0472 (14)0.0430 (11)−0.0009 (10)0.0078 (9)−0.0021 (11)
C120.0420 (12)0.0377 (12)0.0441 (11)0.0013 (10)0.0088 (9)−0.0023 (10)
C130.0534 (13)0.0385 (13)0.0414 (11)−0.0013 (10)0.0019 (9)0.0027 (10)
C140.0571 (15)0.0563 (16)0.0531 (14)0.0004 (12)−0.0033 (11)0.0013 (13)
C150.0656 (16)0.0642 (19)0.0689 (17)−0.0058 (15)−0.0158 (14)0.0039 (15)
C160.100 (2)0.0493 (17)0.0513 (15)−0.0104 (16)−0.0120 (15)−0.0002 (13)
C170.095 (2)0.0578 (18)0.0476 (14)0.0008 (15)0.0035 (14)−0.0093 (13)
C180.0656 (16)0.0528 (16)0.0512 (14)0.0007 (13)0.0065 (11)−0.0057 (12)

Geometric parameters (Å, °)

O1—C21.188 (3)C6—C91.452 (3)
O2—C21.356 (3)C7—C81.378 (3)
O2—C31.404 (2)C7—H70.9300
O3—C111.193 (3)C8—H80.9300
O4—C121.385 (2)C9—C101.343 (3)
O4—C111.394 (3)C9—H90.9300
N1—C121.277 (3)C10—C111.468 (3)
N1—C101.404 (3)C12—C131.460 (3)
C1—C21.481 (3)C13—C141.384 (3)
C1—H1A0.9600C13—C181.390 (3)
C1—H1B0.9600C14—C151.380 (4)
C1—H1C0.9600C14—H140.9300
C3—C81.375 (3)C15—C161.367 (4)
C3—C41.376 (3)C15—H150.9300
C4—C51.374 (3)C16—C171.371 (4)
C4—H40.9300C16—H160.9300
C5—C61.404 (3)C17—C181.377 (3)
C5—H50.9300C17—H170.9300
C6—C71.389 (3)C18—H180.9300
C2—O2—C3119.26 (17)C10—C9—C6129.6 (2)
C12—O4—C11105.40 (16)C10—C9—H9115.2
C12—N1—C10105.77 (17)C6—C9—H9115.2
C2—C1—H1A109.5C9—C10—N1129.26 (19)
C2—C1—H1B109.5C9—C10—C11122.8 (2)
H1A—C1—H1B109.5N1—C10—C11107.96 (18)
C2—C1—H1C109.5O3—C11—O4121.40 (19)
H1A—C1—H1C109.5O3—C11—C10133.7 (2)
H1B—C1—H1C109.5O4—C11—C10104.85 (18)
O1—C2—O2123.0 (2)N1—C12—O4115.99 (18)
O1—C2—C1126.2 (2)N1—C12—C13127.46 (19)
O2—C2—C1110.7 (2)O4—C12—C13116.54 (18)
C8—C3—C4121.5 (2)C14—C13—C18119.5 (2)
C8—C3—O2116.73 (19)C14—C13—C12121.5 (2)
C4—C3—O2121.6 (2)C18—C13—C12119.0 (2)
C5—C4—C3119.5 (2)C15—C14—C13119.9 (3)
C5—C4—H4120.3C15—C14—H14120.1
C3—C4—H4120.3C13—C14—H14120.1
C4—C5—C6120.7 (2)C16—C15—C14120.3 (3)
C4—C5—H5119.7C16—C15—H15119.8
C6—C5—H5119.7C14—C15—H15119.8
C7—C6—C5117.93 (19)C15—C16—C17120.1 (2)
C7—C6—C9118.43 (19)C15—C16—H16119.9
C5—C6—C9123.59 (19)C17—C16—H16119.9
C8—C7—C6121.6 (2)C16—C17—C18120.5 (3)
C8—C7—H7119.2C16—C17—H17119.8
C6—C7—H7119.2C18—C17—H17119.8
C3—C8—C7118.7 (2)C17—C18—C13119.7 (3)
C3—C8—H8120.6C17—C18—H18120.2
C7—C8—H8120.6C13—C18—H18120.2

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: LH5032).

References

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  • Khbnadidah, S., Rezaei, Z., Khalafi-Nehad, A., Bahrinajafi, R., Mohamadi, R. & Farrokroz, A. A. (2003). Bioorg. Med. Chem. Lett 13, 2863–2865. [PubMed]
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