3,5-Bis(benz­yloxy)benzoic acid

Rodolfo Moreno-Fuquen; Carlos Grande; Rigoberto C Advincula; Juan C Tenorio; Javier Ellena

doi:10.1107/S1600536812043796

. 2012 Oct 31;68(Pt 11):o3247–o3248. doi: 10.1107/S1600536812043796

3,5-Bis(benzyloxy)benzoic acid

Rodolfo Moreno-Fuquen ^a,^*, Carlos Grande ^b, Rigoberto C Advincula ^c, Juan C Tenorio ^d, Javier Ellena ^d

PMCID: PMC3515325 PMID: 23284545

Abstract

In the title compound, C₂₁H₁₈O₄, the outer benzyl rings are disordered over two resolved positions in a 0.50 ratio. The O—CH₂ groups form dihedral angles of 4.1 (2) and 10.9 (4)° with the central benzene ring, adopting a syn–anti conformation with respect to this ring. In the crystal, the molecules are linked by O—H⋯O hydrogen bonds and weak C—H⋯O interactions, forming chains along [010].

Related literature

For properties of dendrimer chemistry, see: Fréchet (2002 ▶). For the diverse applications of 3,5-bis(benzyloxy)benzoic acid and its benzoate derivatives, see: Sivakumar et al. (2010 ▶); Remya et al. (2008 ▶); Hawker & Fréchet (1992 ▶). For magnetic and luminiscent properties of lanthanide benzoates, see: Busskamp et al. (2007 ▶). For the conformation of O—CH₂ groups, see: Xiao et al. (2007 ▶). For related structures, see: Gainsford et al. (2009 ▶); Zhu et al. (2009 ▶). For graph-set motifs, see: Etter (1990 ▶). For hydrogen bonding, see: Nardelli (1995 ▶); Desiraju & Steiner (1999 ▶).

Experimental

Crystal data

C₂₁H₁₈O₄
M _r = 334.37
Triclinic,
a = 5.2801 (2) Å
b = 11.6830 (5) Å
c = 14.4803 (7) Å
α = 83.303 (2)°
β = 80.775 (2)°
γ = 79.031 (1)°
V = 862.17 (6) Å³
Z = 2
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 295 K
0.43 × 0.11 × 0.10 mm

Data collection

Nonius KappaCCD diffractometer
5626 measured reflections
3084 independent reflections
1801 reflections with I > 2σ(I)
R _int = 0.036

Refinement

R[F ² > 2σ(F ²)] = 0.053
wR(F ²) = 0.163
S = 1.03
3084 reflections
316 parameters
H-atom parameters constrained
Δρ_max = 0.15 e Å⁻³
Δρ_min = −0.15 e Å⁻³

Data collection: COLLECT (Nonius, 2000 ▶); cell refinement: SCALEPACK (Otwinowski & Minor, 1997 ▶); data reduction: DENZO (Otwinowski & Minor, 1997 ▶) and SCALEPACK; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ▶) and Mercury (Macrae et al., 2006 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Supplementary Material

Click here for additional data file.^{(23.2KB, cif)}

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812043796/hg5257sup1.cif

e-68-o3247-sup1.cif^{(23.2KB, cif)}

Click here for additional data file.^{(151.3KB, hkl)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812043796/hg5257Isup2.hkl

e-68-o3247-Isup2.hkl^{(151.3KB, hkl)}

Click here for additional data file.^{(6.4KB, cml)}

Supplementary material file. DOI: 10.1107/S1600536812043796/hg5257Isup3.cml

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
O2—H2⋯O1ⁱ	0.82	1.82	2.6333 (18)	175
C20—H20⋯O1ⁱⁱ	0.93	2.66	3.507 (13)	153

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

Acknowledgments

RMF is grateful to the Spanish Research Council (CSIC) for the use of a free-of-charge licence to the Cambridge Structural Database. RMF also thanks the Universidad del Valle, Colombia, and CG thanks the Universidad San Buenaventura, Cali, Colombia, for partial financial support.

supplementary crystallographic information

Comment

Dendrimer chemistry provides new opportunities of research in design of supramolecular architectures (Fréchet, 2002). 3,5-Bis-benzyloxy-benzoic acid (I) was used for the synthesis of luminescent lanthanide coordination complexes that display unique line-like emission bands (Sivakumar et al., 2010; Remya et al., 2008). Lanthanide benzoates and their derivatives have potential applications in a wide variety of fields because their novel luminescent and magnetic properties (Busskamp et al., 2007). The title compound was also used in the synthesis of monodispersed dendritic polyesters with removable chain ends using a convergent growth process (Hawker & Fréchet, 1992). Other related compounds were crystallized and studied by X-ray diffraction (Gainsford et al., 2009; Zhu et al., 2009) and their parameters can be used to compare with the parameters of the title system. A perspective view of the molecule of (I), showing the atomic numbering scheme, is given in Fig. 1. The title compound crystallizes in the triclinic system with a P-1 space group. The outer benzyl rings are disordered over two resolved positions in a 0.50 ratio. The molecules are bonded by intermolecular O—H···O hydrogen bonds of moderate character (Desiraju & Steiner, 1999). Indeed, carbonylic O2 and O1 are linked with an O···O distance of 2.633 (2) Å. The propagation of these interactions generate centrosymmetric rings with graphs-set notation R₂²(8) (Etter, 1990). Other weak C—H···O intermolecular interactions (Nardelli, 1995) contribute to stabilization of the molecules along b (Fig. 2). Other classical hydrogen bond interactions are not exhibited in the crystal packing. In the title structure, the O—CH₂ groups adopt a syn-anti conformation with respect to the central phenyl ring, similar to the behavior presented in the 1,3-Dibenzyloxy-5-(bromomethyl)-benzene system (Zhu et al., 2009), while in other similar structures, the O—CH₂ groups adopt a syn-syn conformation (Xiao et al., 2007). The O—CH₂ groups, C4—O3—C8—C9 and C6—O4—C15—C16 are essentially planar (r.m.s. deviation of non-hydrogen atoms= 0.0355 Å and 0.0217 Å respectivelly) and form dihedral angles of 4.1 (2)° and 10.9 (4)° with the central phenyl ring.

Experimental

Methyl 3,5-dihydroxybenzoate (2.0g, 12 mmol) was dissolved in 50 ml of acetonitrile and refluxed with potassium carbonate (8.0 g, 58 mmol) for 30 min. The resulting reaction mixture was refluxed at 68° C for 48 h following the addition of benzyl bromide (4.0 g, 24 mmol). The acetonitrile was evaporated off, and the residual mixture was poured into ice cold water. Methyl 3,5-bis-(benzyloxy)benzoate was obtained as a white precipitate. (2.0 g, 5.74 mmol), were taken from the precipitate, which was dissolved in 50 ml of ethanol. To this solution was added (1 g, 17.77 mmol) of KOH and it was placed under reflux. The reaction was followed by TLC until the presence of KOH was not longer observed. The reaction mixture was poured into ice cold water, acidified with dilute HCl, and the resulting precipitate was filtered, washed, dried, and recrystallized from ethanol. Yield, 1.67 g (89%). 3,5-Bis(benzyloxy)benzoic Acid, ¹H-NMR (500 MHz) δ(p.p.m.), 7.45–7.46(d, 4H, J= 7 Hz), 7.39–7.41 (t, 4H, J=7 Hz), 7.32–7.35 (t, 2H, J= 7 Hz), 7.16(d, 2H, J= 2.5 Hz), 6.92–6.93 (t, 1H, J= 2.5 Hz), 5.15 (s, 4H). ¹³C-NMR: 166.88, 159.35, 136.64, 132.79, 138.45, 127.90, 127.63, 107.96, 106.50, 69.45. F T—IR (KBr): 3033 (Ar—H); 1690, 1159, 733, 698 cm^-1.