4,6-Di-tert-butyl-2,8-dimeth­oxy­dibenzo[b,d]furan

Dayeon Chung; Enkhzul Otgonbaatar; Seok Hwan Son; Minchul Chung; Chee-Hun Kwak

doi:10.1107/S1600536811048379

. 2011 Nov 19;67(Pt 12):o3356. doi: 10.1107/S1600536811048379

4,6-Di-tert-butyl-2,8-dimethoxydibenzo[b,d]furan

Dayeon Chung ^a, Enkhzul Otgonbaatar ^b, Seok Hwan Son ^c, Minchul Chung ^c, Chee-Hun Kwak ^b,^*

PMCID: PMC3239001 PMID: 22199850

Abstract

In the title compound, C₂₂H₂₈O₃, the dihedral angle between the benzene rings is 3.47 (13)° and the five-membered furan ring is essentially planar with a largest deviation of 0.0052 (14) Å. The Csp ²—Csp ² bond length between the two benzene rings [1.443 (3) Å] is considerably shorter than those between the benzene and tertiary C atoms [1.538 (3) and 1.530 (3) Å], which are sp ²–sp ³ hybridized. C—H⋯π interactions involving the furan and benzene rings are found in the crystal structure.

Related literature

For the synthesis of the title compound, see: Hewgill & Hewitt (1967 ▶); Butsgan et al. (1989 ▶); Malkowsky et al. (2006 ▶). For a related structure, see: Du & Wang (2009 ▶).

Experimental

Crystal data

C₂₂H₂₈O₃
M _r = 340.44
Monoclinic,
a = 15.631 (3) Å
b = 8.2487 (14) Å
c = 16.000 (3) Å
β = 105.438 (5)°
V = 1988.5 (6) Å³
Z = 4
Mo Kα radiation
μ = 0.07 mm⁻¹
T = 100 K
0.5 × 0.4 × 0.2 mm

Data collection

Rigaku R-AXIS RAPID II-S diffractometer
Absorption correction: multi-scan (RAPID-AUTO; Rigaku, 2008 ▶) T _min = 0.965, T _max = 0.985
18260 measured reflections
4563 independent reflections
2123 reflections with I > 2σ(I)
R _int = 0.107

Refinement

R[F ² > 2σ(F ²)] = 0.076
wR(F ²) = 0.229
S = 0.99
4563 reflections
227 parameters
H-atom parameters not refined
Δρ_max = 0.24 e Å⁻³
Δρ_min = −0.21 e Å⁻³

Data collection: RAPID-AUTO (Rigaku, 2008 ▶); cell refinement: RAPID-AUTO; data reduction: RAPID-AUTO; 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: WinGX (Farrugia, 1999 ▶).

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536811048379/bq2314sup1.cif

e-67-o3356-sup1.cif^{(19.4KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811048379/bq2314Isup2.hkl

e-67-o3356-Isup2.hkl^{(217.6KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536811048379/bq2314Isup3.cml

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

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

Cg1 and Cg2 are the centroids of the C5–C8/C11/C12 and O1/C9–C12 rings, respectively.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C15—H15A⋯Cg1ⁱ	0.96	2.98	3.580 (3)	121
C15—H15B⋯Cg2ⁱ	0.96	2.65	3.200 (3)	117
C22—H15A⋯Cg2ⁱⁱ	0.96	2.99	3.872 (4)	152

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

Acknowledgments

This work was supported financially by the RIC, 2011, and the Non-Directional Fund of Sunchon National University, 2005.

supplementary crystallographic information

Comment

Oxidative coupling of phenyl is a useful synthetic route for the synthesis of natural products (Malkowsky et al., 2006). 2-tert-Butyl-4-methoxyphenol (BHA) is well kwon as an antioxidant and oxidative coupling of it produces di-BHA and benzofuran derivative by the various method of preparation (Hewgill & Hewitt, 1967; Butsgan et al., 1989). The single-crystal structure of di-BHA was reported but that of benzofuran derived from BHA has not been investigated. Here we describe the structure of title compound obtained from pyrolysis method.

The title compound, C₂₂H₂₉O₃, forms tricycle adjoined two benzene skeleton in C10 and C11, and C9 and C12 through O1 (Fig. 1). All atoms lies in almost a plane, the dihedral angle between two benzene skeletons is 3.47 (13)° and 5-membered furan ring is a plane with the largest deviation of 0.0052 (14) Å. The bond distance of C10—C11 [1.443 (3) Å] in sp² –sp² hybridization, which connects two benzene skeleton, is considerably shorter than that of C1—C13 [1.538 (3) Å] or C8—C14 [1.530 (3) Å] in sp²-sp³ hybridization. C15—H15A···π (3/2 - x, 1/2 + y, 1/2 - z) interaction involving the benzene ring (C5-C8/C11-C12) and, C15—H15B···π and C22—H22A···π (2 - x, 2 - y, -z) interactions involing furan ring (O1/C9—C12) are found in the crystal structure (Fig. 2 and Table 1). No classical hydrogen bond is found in the crystal structure.

Experimental

A mixture of BHA (1.20 g, 6.65 mmol) and iron (0.95 g) and copper (0.89 g) powder in a Schlenk tube was heated under argon gas until BHA was melt and this mixture keep ca 170°C for 24 h. Dissolving the product with 30 ml CH₂Cl₂ for 3 times, the solution was chromatographed on Al₂O₃ eluting with CH₂Cl₂/n-hexane(1:1) to afford the title compound. Single crystals of the compound for X-ray analysis were obtained by recrystallization from CH₂Cl₂/n-hexane (1:1) at -20°C. ¹³C-NMR (THF-d⁵) δ 29.245 (C(CH₃)₃), 32.843 ((O-CH₃), 54.707 (C(CH₃)₃), 11.825, 113.253, 128.572, 139.625, 145.875, 153.619 (Phenyl). ESI-MS (M/z) C₂₂H₂₈O₃; Observed (cal'd): [M+H]⁺ = 341.2186 (340.46).