N-[4-(4-Nitro­phen­oxy)phen­yl]propionamide

Asifa Nigar; Zareen Akhter; Michael Bolte; Humaira M Siddiqi; Rizwan Hussain

doi:10.1107/S1600536808034119

. 2008 Oct 25;64(Pt 11):o2186. doi: 10.1107/S1600536808034119

N-[4-(4-Nitrophenoxy)phenyl]propionamide

Asifa Nigar ^a, Zareen Akhter ^a,^*, Michael Bolte ^b, Humaira M Siddiqi ^a, Rizwan Hussain ^c

PMCID: PMC2959666 PMID: 21581044

Abstract

The title compound, C₁₅H₁₄N₂O₄, is an important intermediate for the synthesis of thermotropic liquid crystals. The dihedral angle between the two aromatic rings is 84.29 (4)°. An N—H⋯O hydrogen bond connects the molecules into chains running along the b axis. In addition, the crystal packing is stabilized by weak C—H⋯O hydrogen bonds.

Related literature

For background on liquid crystals, see: Bahadur (1992 ▶); Collings (1990 ▶); Collings & Hird (1997 ▶). For bond lengths and angles in organic compounds, see: Allen et al. (1995 ▶). For related literature, see: Akhter et al. (2007 ▶); Cârlescu et al. (2005 ▶).

Experimental

Crystal data

C₁₅H₁₄N₂O₄
M _r = 286.28
Monoclinic,
a = 14.8597 (14) Å
b = 5.2400 (3) Å
c = 17.9034 (16) Å
β = 101.875 (7)°
V = 1364.21 (19) Å³
Z = 4
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 173 (2) K
0.37 × 0.28 × 0.19 mm

Data collection

Stoe IPDSII diffractometer
Absorption correction: none
16399 measured reflections
2788 independent reflections
2347 reflections with I > 2σ(I)
R _int = 0.048

Refinement

R[F ² > 2σ(F ²)] = 0.036
wR(F ²) = 0.096
S = 1.03
2788 reflections
195 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.28 e Å⁻³
Δρ_min = −0.19 e Å⁻³

Data collection: X-AREA (Stoe & Cie, 2001 ▶); cell refinement: X-AREA; data reduction: X-RED (Stoe & Cie, 2001 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: XP in SHELXTL-Plus (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808034119/wm2199sup1.cif

e-64-o2186-sup1.cif^{(18.1KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808034119/wm2199Isup2.hkl

e-64-o2186-Isup2.hkl^{(136.9KB, hkl)}

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

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯O1ⁱ	0.825 (17)	2.255 (17)	3.0306 (13)	156.7 (15)
C25—H25⋯O3ⁱⁱ	0.95	2.42	3.2082 (17)	140
C23—H23⋯O4ⁱⁱⁱ	0.95	2.53	3.3400 (16)	144

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) .

Acknowledgments

The authors are grateful to the Department of Chemistry, Quaid-I-Azam University, Islamabad, Pakistan, the Institute for Inorganic Chemistry, University of Frankfurt, Germany, and NESCOM, PO Box 2166, Islamabad, Pakistan, for providing laboratory and analytical facilities.

supplementary crystallographic information

Comment

Liquid crystals are materials which exhibit phases where molecular order is intermediate between that of an ordered solid and a disordered liquid. They represent the combined properties of both the crystalline state (e.g. optical and electrical anisotropy) and the liquid state (e.g. molecular mobility and fluidity). The two major classes of liquid crystals are thermotropic and lyotropic, which can be distinguished by the mechanism that drive their self-organization. Background information on liquid crystals and their various applications were surveyed, for example, by Collings (1990), Bahadur (1992), and Collings & Hird (1997). One of the basic characteristics for the establishment of the mesophase is the ratio of rigid and flexible portions in the main structure (Cârlescu et al., 2005). Therefore such type of precursors can be used to study structure property relationship of the liquid crystalline materials.

The crystal structure of the compound reported here is an important intermediate for the synthesis of thermotropic liquid crystals (Akhter et al., 2007).

In the molecule of the title compound (Fig. 1), the bond lengths (Allen et al., 1995) and angles are within normal ranges.

The dihedral angle between the two aromatic rings is 84.29 (4)°. An N—H···O hydrogen bond connects the molecules to chains running along the b axis. In addition, the crystal packing is stabilized by weak C—H···O hydrogen bonds.

Experimental

A mixture of 5.046 g (50 mmol) 4-aminophenol, 6.91 g (50 mmol) anhydrous K₂CO₃ and 5.3 ml (50 mmol) 4-nitrofluorobenzene in 70 ml DMF was heated at 373 K for 18 h in an inert atmosphere. After cooling to room temperature, the reaction mixture was poured into 800 ml of water to yield a yellow solid. The product was filtered, dried and then re-crystallized from n-hexane (yield 86%). In a second step, propanoic acid and thionylchloride were refluxed in equimolar amounts for 30 min before evaporating excessive thionylchloride with a vacuum pump. The above prepared 4-[4-nitrophenoxy]aniline was then added to the propanoyl chloride solution in dry THF. 1 ml of triethylamine was also added for 1 g of 4-[4-nitrophenoxy]aniline and refluxed for 2 h under inert conditions. The reaction mixture was allowed to stand at room temperature overnight and filtered off the salt formed. The filterate was evaporated using a rotary evaporator, and the crude product obtained was re-crystallized from toluene (yield 76%, m.p. 416 K).