4′-Formyl­benzo-15-crown-5

Conrad Fischer; Stefanie F Helas; Wilhelm Seichter; Edwin Weber; Bakhtiyar T Ibragimov

doi:10.1107/S1600536808022186

. 2008 Jul 19;64(Pt 8):o1556. doi: 10.1107/S1600536808022186

4′-Formylbenzo-15-crown-5

Conrad Fischer ^a, Stefanie F Helas ^a, Wilhelm Seichter ^a, Edwin Weber ^a, Bakhtiyar T Ibragimov ^b,^*

PMCID: PMC2962178 PMID: 21203259

Abstract

In the title compound (systematic name: 17-formyl-2,5,8,11,14-pentaoxabicyclo[13.4.0]nonadeca-15,17,19-triene), C₁₅H₂₀O₆, the 15-crown-5 ring adopts a twisted conformation. The formyl group is coplanar with the benzene ring. The crystal packing is stabilized by C—H⋯O interactions involving the C=O group and ether O atoms as acceptors and methylene CH groups as donors.

Related literature

The unsubstituted benzocrown ether was characterized by Pedersen (1967 ▶) and its structure was described by Hanson (1978 ▶), while Rogers and co-workers reported 4′-amino- and 4′-nitro-substituted compounds (Rogers, Huggins et al., 1992 ▶; Rogers, Henry & Rollins, 1992 ▶). For the synthesis of the title compound, see: Hyde et al. (1978 ▶).

Experimental

Crystal data

C₁₅H₂₀O₆
M _r = 296.31
Monoclinic,
a = 18.0091 (8) Å
b = 9.6678 (4) Å
c = 8.1028 (3) Å
β = 91.262 (2)°
V = 1410.42 (10) Å³
Z = 4
Mo Kα radiation
μ = 0.11 mm⁻¹
T = 90 (2) K
0.60 × 0.39 × 0.05 mm

Data collection

Bruker Kappa APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2004 ▶) T _min = 0.857, T _max = 0.995
18190 measured reflections
4523 independent reflections
3716 reflections with I > 2σ(I)
R _int = 0.026

Refinement

R[F ² > 2σ(F ²)] = 0.037
wR(F ²) = 0.116
S = 1.00
4523 reflections
190 parameters
H-atom parameters constrained
Δρ_max = 0.28 e Å⁻³
Δρ_min = −0.22 e Å⁻³

Data collection: APEX2 (Bruker, 2004 ▶); cell refinement: SAINT (Bruker, 2004 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808022186/gk2144sup1.cif

e-64-o1556-sup1.cif^{(18.9KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808022186/gk2144Isup2.hkl

e-64-o1556-Isup2.hkl^{(221.6KB, 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
C13—H13B⋯O4ⁱ	0.99	2.55	3.3351 (10)	137
C14—H14A⋯O5ⁱⁱ	0.99	2.66	3.1700 (12)	112
C8—H8A⋯O1ⁱⁱⁱ	0.99	2.66	3.3775 (13)	130

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

Acknowledgments

Financial support from the German Federal Ministry of Economics and Technology (BMWi) under grant No. 16IN0218 ‘ChemoChips’ is gratefully acknowledged. We thank Dr Tobias Gruber for fruitful discussions.

supplementary crystallographic information

Comment

The title compound is a derivative of benzo-15-crown-5 (Pedersen, 1967). It was prepared as part of our studies concerning fluorogenic receptor molecules with possible analytical applications. The O-C-C-O torsion angles within the polyether ring are (±)gauche [69.34° (10), -71.10°(8), -65.61°(11)) and anti (168.42°(9)]) resulting in a twisted crown ether conformation. In the title molecule, the dihedral angle between the aromatic ring plane and the mean plane of ether oxygen atoms is 20.67 (5)°. Worth to note, the torsion angle C3—C4—C7—O1 is 179.75 (10)°, indicating only a very small twist of the formyl group relative to the aromatic ring. Thus, in agreement with a previous report (Rogers, Huggins et al., 1992; Rogers, Henry & Rollins, 1992), the substituent on the benzene ring has negligible influence on the conformation of the benzo-15-crown-5 (Hanson, 1978). Owing to the absence of strong hydrogen bond donors, the crystal packing is stabilized by weak C—H···O hydrogen bonds, involving the O atoms of the crown ether and C==O group as acceptors, and the methylene C-H groups as donors (Table 1). In addition, π—π interaction has also been detected, resulting in a stacking of the molecules along the crystallographic c axis with a distance of 4.211 (2) Å between the centroids of two neighboring aromatic rings (Fig.2).

Experimental

The title compound, 4'-formylbenzo-15-crown-5, was synthesized from benzo-15-crown-5 (Pedersen, 1967) which was reacted with N-methylformanilide and phoshoryl chloride (Hyde et al., 1978). Colourless needles of the title compound suitable for X-ray diffraction analysis were obtained by slow cooling and evaporation of a solution of n-heptane. Fast cooling of the solution resulted in the formation of an orthorhombic polymorph of the title compound.