4-(4-Octyloxybenzo­yloxy)benzoic acid

Khushi Muhammad; M Khawar Rauf; Masahiro Ebihara; Shahid Hameed

doi:10.1107/S1600536809003298

. 2009 Jan 31;65(Pt 2):o424. doi: 10.1107/S1600536809003298

4-(4-Octyloxybenzoyloxy)benzoic acid

Khushi Muhammad ^a, M Khawar Rauf ^a, Masahiro Ebihara ^b, Shahid Hameed ^a,^*

PMCID: PMC2968365 PMID: 21582012

Abstract

The title compound, C₂₂H₂₆O₅, is an important intermediate for the synthesis of side-chain ligands for polymeric liquid crystals. The octyl group is coplanar with the central C₆O moiety, where the maximum deviation of a C atom in the octyl group from the C₆O plane is 0.161 (5) Å. The crystal structure is stabilized by intermolecular O—H⋯O hydrogen bonds.

Related literature

For studies of aromatic carboxylic acids and their applications, see: Naoum et al. (2008 ▶); Nazir et al. (2008a ▶,b ▶); Gabert et al. (2006 ▶); Aranzazu et al. (2006 ▶); Hussain et al. (2005 ▶); Shafiq et al. (2005 ▶); Ahmad et al. (2003 ▶); Ribeiro et al. (2008 ▶); Hameed & Rama (2004 ▶); For related structures, see: Muhammad et al. (2008 ▶); Hartung et al. (1997 ▶)

Experimental

Crystal data

C₂₂H₂₆O₅
M _r = 370.43
Monoclinic,
a = 13.528 (8) Å
b = 7.245 (4) Å
c = 20.903 (12) Å
β = 111.407 (8)°
V = 1907.5 (18) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 123 K
0.40 × 0.30 × 0.15 mm

Data collection

Rigaku/MSC Mercury CCD diffractometer
Absorption correction: none
14669 measured reflections
4358 independent reflections
3870 reflections with I > 2σ(I)
R _int = 0.048

Refinement

R[F ² > 2σ(F ²)] = 0.081
wR(F ²) = 0.138
S = 1.31
4358 reflections
247 parameters
H-atom parameters constrained
Δρ_max = 0.28 e Å⁻³
Δρ_min = −0.19 e Å⁻³

Data collection: CrystalClear (Molecular Structure Corporation & Rigaku, 2001 ▶); cell refinement: CrystalClear; data reduction: TEXSAN (Molecular Structure Corporation & Rigaku, 2004 ▶); program(s) used to solve structure: SIR97 (Altomare et al., 1999 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEPII (Johnson, 1976 ▶); software used to prepare material for publication: SHELXL97 and TEXSAN.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809003298/hg2473sup1.cif

e-65-0o424-sup1.cif^{(21KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809003298/hg2473Isup2.hkl

e-65-0o424-Isup2.hkl^{(213.6KB, 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
O3—H3O⋯O4ⁱ	0.84	1.85	2.659 (3)	161
O4—H4O⋯O3ⁱ	0.84	1.83	2.659 (3)	171

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Symmetry code: (i) Inline graphic .

Acknowledgments

MKR is grateful to the Higher Education Commission of Pakistan for financial support under the International Support Initiative Programme for a doctoral fellowship at Gifu University, Japan.

supplementary crystallographic information

Comment

Aromatic carboxylic acids bearing different substituents have been investigated for their liquid crystalline properties (Naoum et al., 2008; Nazir et al., 2008a,b). Such acids have been utilized in the synthesis of both side-chain (Gabert et al., 2006) and main-chain (Aranzazu et al., 2006) liquid crystal polymers. In addition to their use as intermediates in the synthesis of a large number of organic compounds (Hussain et al., 2005; Shafiq et al., 2005; Ahmad et al., 2003), carboxylic acids has also been used in the pharmaceutical industry (Ribeiro et al., 2008; Hameed & Rama 2004). The title compound (I) was synthesized as an intermediate in the synthesis of side-chain liquid crystal polymers. In the present report, the crystal structure of (I) is being presented. Bond lengths and angles are within the normal ranges as given for benzoyloxybenzoic acids (Muhammad et al., 2008; Hartung et al., 1997). The C7—O1 and C7—O2 bond lengths are 1.205 (3) and 1.369 (3) Å, respectively, that reflect their double and single bond character. The very similar bond lengths of C14—O4 and C14—O3, 1.287 (3) and 1.261 (3) Å, are due to disorder of CO₂H moiety. The octyl group is coplanar with the central C₆O moiety where the max dviation of C atom in octyl group from the C₆O moiety is 0.161 (5) Å. Two molecules related by an inversion center form a dimer via two hydrogen bonds composed of two carboxyl groups as shown in Fig. 2.

Experimental

To a solution of 4-hydroxybenzaldehyde (0.032 moles) in 50 ml of triethylamine (TEA), was added an equivalent amount of 4-octyloxybenzoylchloride with stirring and the mixture heated at 60°C for 1 h. The excess TEA was removed in vacuo and the product, after recrystallization from hot ethanol, was subjected to KMnO₄ oxidation.The 4-(4-octyloxybenzoyloxy)benzaldehyde (0.025 moles) was dissolved in acetone (100 ml) and aqueous KMnO₄ (0.025 moles) was added dropwise at room temperature with stirring. The stirring was continued for three hours when the reaction mixture was filtered and the filtrate acidified using 6M HCl. The precipitated product was purified by recrystallization from acetone.