Crystal structure of 4-(4-meth­oxy­phen­oxy)benzaldehyde

Andreas Schäfer; Ljuba Iovkova-Berends; Stefan Gilke; Paul Kossmann; Hans Preut; Martin Hiersemann

doi:10.1107/S2056989015022707

. 2015 Dec 6;71(Pt 12):o1021. doi: 10.1107/S2056989015022707

Crystal structure of 4-(4-methoxyphenoxy)benzaldehyde

Andreas Schäfer ^a, Ljuba Iovkova-Berends ^a, Stefan Gilke ^a, Paul Kossmann ^a, Hans Preut ^a,^*, Martin Hiersemann ^a

PMCID: PMC4719957 PMID: 26870476

Abstract

The title compound, C₁₄H₁₂O₃, was synthesized via the nucleophilic addition of 4-methoxyphenol to 4-fluorobenzaldehyde. The dihedral angle between the least-squares planes of the benzene rings is 71.52 (3)° and the C—O—C angle at the central O atom is 118.82 (8)°. In the crystal, weak C—H⋯O hydrogen bonds link the molecules to generate supramolecular layers in the bc plane. The layers are linked by weak C—H⋯π interactions.

Keywords: crystal structure, nucleophilic aromatic substitution, benzaldehyde

Related literature

For the synthesis of 4-(4-methoxyphenoxy)benzaldehyde in an undergraduate laboratory course, see: Taber & Brannick (2015 ▸). For the synthesis of 4-aryloxybenzaldehydes and acetophenones, see: Yeager & Schissel (1991 ▸).

Experimental

Crystal data

C₁₄H₁₂O₃
M _r = 228.24
Monoclinic,
a = 12.1297 (7) Å
b = 7.6581 (4) Å
c = 12.3577 (7) Å
β = 103.769 (6)°
V = 1114.92 (11) Å³
Z = 4
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 173 K
0.56 × 0.40 × 0.30 mm

Data collection

Oxford Diffraction Xcalibur2 CCD diffractometer
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2008 ▸) T _min = 0.808, T _max = 1.000
10049 measured reflections
2967 independent reflections
2551 reflections with I > 2σ(I)
R _int = 0.023

Refinement

R[F ² > 2σ(F ²)] = 0.040
wR(F ²) = 0.112
S = 1.04
2967 reflections
155 parameters
H-atom parameters constrained
Δρ_max = 0.28 e Å⁻³
Δρ_min = −0.22 e Å⁻³

Data collection: CrysAlis PRO (Oxford Diffraction, 2008 ▸); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS2014 (Sheldrick, 2008 ▸); program(s) used to refine structure: SHELXL2013 (Sheldrick, 2015 ▸); molecular graphics: SHELXP2014 (Sheldrick, 2008 ▸); software used to prepare material for publication: SHELXL2013 and PLATON (Spek, 2009 ▸).

Supplementary Material

Crystal structure: contains datablock(s) I, 3352b. DOI: 10.1107/S2056989015022707/tk5411sup1.cif

e-71-o1021-sup1.cif^{(329.6KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989015022707/tk5411Isup2.hkl

e-71-o1021-Isup2.hkl^{(237.2KB, hkl)}

Click here for additional data file.^{(4.5KB, cml)}

Supporting information file. DOI: 10.1107/S2056989015022707/tk5411Isup3.cml

Click here for additional data file.^{(1.3MB, tif)}

. DOI: 10.1107/S2056989015022707/tk5411fig1.tif

The molecular structure of the title compound, showing the labelling of all non-H atoms. Displacement ellipsoids are shown at the 50% probability level.

CCDC reference: 1439095

Additional supporting information: crystallographic information; 3D view; checkCIF report

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

Cg1 and Cg2 are the centroids of the C2–C7 and C8–C13 rings, respectively.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C13—H13A⋯O1ⁱ	0.95	2.58	3.5129 (14)	167
C7—H7A⋯O1ⁱⁱ	0.95	2.56	3.2500 (14)	130
C1—H1A⋯Cg1ⁱⁱⁱ	0.95	2.73	3.5453 (12)	145
C10—H10A⋯Cg2^iv	0.95	2.88	3.7465 (12)	152

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

Acknowledgments

The TU Dortmund is greatefully acknowledged for financial support.

supplementary crystallographic information

S1. Comment

As part of an evaluation of single step experiments for an undergraduate laboratory course, we came across a literature protocol that describes the preparation of crystalline 4-aryloxybenzaldehyde by nucleophilic aromatic substitution (Taber & Brannick, 2015). The reaction of 4-fluorobenzaldehyde (II) with 4-methoxyphenol (III) in the presence of potassium carbonate in dimethyl sulfoxide provided 4-(4-methoxyphenoxy)benzaldehyde (I) as large pale yellow crystals. The recrystallization of a small amount of (I) from n-heptane provided clear colourless crystals, suitable for X-ray analysis. In our hands, the literature protocol failed to deliver precipitated crude product upon dilution of the reaction mixture with water and subsequent drying on filter paper. Our modified protocol is characterized by a general aqueous work-up procedure, including extraction with brine for removal of dimethyl sulfoxide.

S2. Experimental

In a glass test tube (160x16 mm) 4-fluorobenzaldehyde (II) (C₇H₅FO, M =124.11 g/mol, 250 mg, 2.01 mmol, 1 eq), 4-methoxyphenol (III) (C₇H₈O₂, M = 124.14 g/mol, 250 mg, 2.01 mmol, 1 eq) and potassium carbonate (K₂CO₃, M = 138.20 g/mol, 550 mg, 3.98 mmol, 2 eq) were suspended in dimethyl sulfoxide (2 ml, 1 ml/mmol). The reaction mixture was heated to 413 K and stirred at this temperature for 45 min. After consumption of the starting materials, the oil bath was removed and the suspension was cooled to room temperature. The reaction mixture was diluted with water (6 ml, 3 ml/mmol) and stirred at ambient temperature for 30 min. The resulting suspension was tranferred into a separatory funnel with water and then extracted with ethyl acetate (3x). The combined organic phases were extracted with saturated aqueous sodium chloride solution (5x) and dried over MgSO₄. After removal of the solvents under reduced pressure, the light brown viscous oil was dissolved in dichloromethane (2 ml) and transferred into a wide-necked flask. The solution was diluted with n-heptane (1 ml) and the solvent was allowed to evaporate over three days. Crystals slowly form and grow, coating the sides of the flask. The large pale yellow crystals were washed with n-heptane (1 ml) and dried in vacuo to deliver 4-(4-methoxyphenoxy)benzaldehyde (I) (C₁₄H₁₂O₃, M = 228.25 g/mol, 440 mg, 1.93 mmol, 96%). Recrystallization of a small amount of (I) from n-heptane by slow evaporation over one week provided clear colourless crystals. R_f 0.48 (cyclohexane/ethyl acetate 5/1); m.p. 323–325 K (n-heptane) [m.p. 332.5–333.5 K (n-hexane) (Yeager & Schissel, 1991)]; ¹H NMR (CDCl₃, 500 MHz) δ 3.83 (s, 3H), 6.92–6.95 (m, 2H), 6.99–7.05 (m, 4H), 7.81–7.83 (m, 2H), 9.90 (s, 1H); ¹³C NMR (CDCl₃, 126 MHz) δ 55.8 (CH₃), 115.3 (CH), 116.9 (CH), 122.0 (CH), 131.0 (C), 132.1 (CH), 148.3 (C), 157.0 (C), 164.2 (C), 190.9 (CH); IR ν 3005 (w), 2965 (w), 2835 (w), 2745 (w), 1680 (s), 1595 (m), 1575 (s), 1495 (s), 1440 (m), 1230 (s), 1195 (s), 1150 (s), 1100 (m), 1085 (s), 875 (m), 845 (m), 830 (s), 785 (s), 745 (m), 565 (m), 525 (m), 510 (s).