2,7-Dimeth­oxy-1,8-bis­(4-phen­oxy­benzo­yl)naphthalene

Daichi Hijikata; Teruhisa Takada; Atsushi Nagasawa; Akiko Okamoto; Noriyuki Yonezawa

doi:10.1107/S1600536810042170

. 2010 Oct 23;66(Pt 11):o2902–o2903. doi: 10.1107/S1600536810042170

2,7-Dimethoxy-1,8-bis(4-phenoxybenzoyl)naphthalene

Daichi Hijikata ^a, Teruhisa Takada ^a, Atsushi Nagasawa ^a, Akiko Okamoto ^a, Noriyuki Yonezawa ^a,^*

PMCID: PMC3009209 PMID: 21589079

Abstract

In the title molecule {systematic name: [2,7-dimethoxy-8-(4-phenoxybenzoyl)naphthalen-1-yl](4-phenoxyphenyl)methanone}, C₃₈H₂₈O₆, the 4-phenoxybenzoyl units adopt a syn orientation with respect to the naphthalene ring system. The internal benzene rings, A and B, make dihedral angles of 86.72 (5) and 79.22 (5)° with the naphthalene ring system. The two terminal benzene rings, C and D, of the 4-phenoxybenzoyl groups are twisted with respect to benzene rings A and B, with dihedral angles of A/C = 62.72 (8) and B/D = 87.61 (6)°. In the crystal, H atoms in the naphthalene system make two types of intermolecular C—H⋯O interactions with the carbonyl O atom and the phenyl etheral O atom of neighbouring molecules. Molecules are further linked by C—H⋯π interactions involving a H atom of terminal benzene ring D and the π-system of the internal benzene ring A, forming dimers centered about an inversion center.

Related literature

For the syntheses of aroylated naphthalene compounds via electrophilic aromatic substitution of naphthalene derivatives, see: Okamoto & Yonezawa (2009 ▶). For the structures of closely related compounds, see: Nakaema et al. (2007 ▶, 2008 ▶); Mitsui et al. (2010 ▶); Muto et al. (2010 ▶); Watanabe et al. (2010a ▶,b ▶).

Experimental

Crystal data

C₃₈H₂₈O₆
M _r = 580.60
Monoclinic,
a = 12.0733 (4) Å
b = 12.4806 (4) Å
c = 19.8094 (6) Å
β = 91.115 (2)°
V = 2984.36 (15) Å³
Z = 4
Cu Kα radiation
μ = 0.71 mm⁻¹
T = 193 K
0.50 × 0.30 × 0.30 mm

Data collection

Rigaku R-AXIS RAPID diffractometer
Absorption correction: numerical (NUMABS; Higashi, 1999 ▶) T _min = 0.720, T _max = 0.816
54106 measured reflections
5458 independent reflections
4862 reflections with I > 2σ(I)
R _int = 0.038

Refinement

R[F ² > 2σ(F ²)] = 0.036
wR(F ²) = 0.099
S = 1.04
5458 reflections
400 parameters
H-atom parameters constrained
Δρ_max = 0.16 e Å⁻³
Δρ_min = −0.13 e Å⁻³

Data collection: PROCESS-AUTO (Rigaku, 1998 ▶); cell refinement: PROCESS-AUTO; data reduction: CrystalStructure (Rigaku/MSC, 2004 ▶); program(s) used to solve structure: SIR2004 (Burla et al., 2005 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEPIII (Burnett & Johnson, 1996 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810042170/su2217sup1.cif

e-66-o2902-sup1.cif^{(27.5KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810042170/su2217Isup2.hkl

e-66-o2902-Isup2.hkl^{(261.9KB, hkl)}

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

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

Cg3 is the centroid of ring A (C12–C17).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C3—H3⋯O2ⁱ	0.95	2.44	3.1479 (17)	131
C6—H6⋯O6ⁱⁱ	0.95	2.56	3.3293 (16)	138
C35—H35⋯Cg3ⁱⁱⁱ	0.95	2.78	3.6528 (17)	153

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

Acknowledgments

The authors express their gratitude to Professor Keiichi Noguchi, Instrumentation Analysis Center, Tokyo University of Agriculture & Technology, for his technical advice. This work was partially supported by the Ogasawara Foundation for the Promotion of Science & Engineering, Tokyo, Japan.

supplementary crystallographic information

Comment

In the course of our studies on selective electrophilic aromatic aroylation of 2,7-dimethoxynaphthalene, peri-aroylnaphthalene compounds have proved to be formed regioselectively by the aid of a suitable acidic mediator (Okamoto & Yonezawa, 2009). Recently, we reported on the crystal structures of three such compounds, 1,8-dibenzoyl-2,7-dimethoxynaphthalene (Nakaema et al., 2008), bis(4-bromophenyl)(2,7-dimethoxynaphthalene-1,8-diyl)dimethanone (Watanabe et al., 2010a), and 1,8-bis(4-methylbenzoyl)-2,7-dimethoxynaphthalene (Muto et al., 2010). The aroyl groups at the 1,8-positions of the naphthalene rings in these compounds are twisted almost perpendicularly but a little tilted toward the exo sides against the naphthalene ring. In addition, 1,8-bis(4-chlorobenzoyl)-7-methoxynaphthalen-2-ol ethanol monosolvate (Mitsui et al., 2010), which was formed by selective demethylation at the 2-methoxy group of 1,8-bis(4-chlorobenzoyl)-2,7-dimethoxynaphthalene (Nakaema et al., 2007), solely has two syn-oriented chlorobenzoyl groups bonding to the naphthalene ring system, and in this molecule the 2-hydroxy group forms intramolecular hydrogen bonds with the carbonyl oxygen atom. As a part of our continuous studies on the molecular structures of this kind of homologous molecules, the crystal structure of the title compound, 1,8-bis(4-phenoxybenzoyl)-2,7-dimethoxynaphthalene, synthesized via nucleophilic aromatic substitution of (2,7-dimethoxynaphthalene-1,8-diyl)bis(4-fluorophenyl)dimethanone (Watanabe et al., 2010b), is reported herein.

In the title molecule, illustrated in Fig. 1, two intervenient benzene rings, A (C12–C17) and B (C25–C30), are in a syn orientation with respect to the naphthalene ring system (C1–C10), and make dihedral angles of 86.72 (5) and 79.22 (5)°, respectively, with the naphthalene ring system. Furthermore, the dihedral angles between benzene rings A and B and the terminal benzene rings C (C18–C23) and D (C31–C36)] are A/C = 62.72 (8), B/D = 87.61 (6)°. Benzene rings A and B are configurated almost parallel to one another, the dihedral angle A/B being only 12.20 (6)°. On the other hand, benzene rings C and D are far from being parallel to one another with a dihedral angle C/D of 64.10 (8)°.

In the crystal, hydrogen atoms in the naphthalene ring form two types of intermolecular C—H···O interactions with the carbonyl oxygen atom (C3—H3···O2ⁱ = 2.44 Å; see Fig. 2 and Table 1) and the phenyl ethereal oxygen atom (C6—H6···O6ⁱⁱ = 2.56 Å; see Fig. 2 and Table 1). Moreover, molecules are linked by C—H···π interactions forming dimeric pairs. The terminal benzene ring D acts as a hydrogen-bond donor and the π system of the intervenient benzene ring A (with centroid Cg3) of an adjacent molecule acts as an acceptor (C35—H35···Cg3ⁱⁱⁱ = 2.78 Å; see Fig. 3 and Table 1).

Experimental

In a 10 ml one-necked flask equipped with a condenser, (2,7-dimethoxynaphthalene-1,8-diyl)bis(4-fluorophenyl)dimethanone (1.0 mmol, 432.4 mg), phenol (4.0 mmol, 376.4 mg), potassium carbonate (8.0 mmol, 1.10 g) and freshly distilled DMAc (2.0 ml) were stirred at 423 K for 6 h. This mixture was then added dropwise into methanol (20 ml) resulting in the formation of a pale yellow precipitate. The crude material was purified by column chromatography (silica gel, hexane: AcOEt= 2:1) to give the title compound (yield 104 mg, 18%). The isolated product was recrystallized from acetone to give block-like yellow single-crystals of the title compound. M.p. 441.6–444.4 K; ¹HNMR δ (300 MHz, CDCl₃): 3.72 (6H, s), 6.82–6.94 (4H, m), 7.09 (4H, d, J=7.5 Hz), 7.14–7.21 (4H, m), 7.36 (4H, t, J=8.4 Hz), 7.55–7.78 (4H,m), 7.92 (2H, d, J=7.5 Hz) p.p.m.; ¹³CNMR δ (75 MHz, CDCl₃): 56.442, 111.128, 116.575, 120.274, 121.440, 124.345, 125.415, 129.467, 129.850, 131.360, 131.876, 133.424, 155.405, 155.998, 161.474, 195.057 p.p.m.; IR (KBr): 1673 (C=O), 1267 (Ar—O—Me) cm^-1; HRMS (m/z): [M + H]⁺ calcd for C₃₈H₂₉O₆, 581.1964 found, 581.82.