[2,7-Dimethoxy-8-(4-methylbenzoyl)-1-naphthyl](4-methylphenyl)methanone

Toyokazu Muto; Yuichi Kato; Atsushi Nagasawa; Akiko Okamoto; Noriyuki Yonezawa

doi:10.1107/S1600536810039620

. 2010 Oct 9;66(Pt 11):o2752. doi: 10.1107/S1600536810039620

[2,7-Dimethoxy-8-(4-methylbenzoyl)-1-naphthyl](4-methylphenyl)methanone

Toyokazu Muto ^a, Yuichi Kato ^a, Atsushi Nagasawa ^a, Akiko Okamoto ^a, Noriyuki Yonezawa ^a,^*

PMCID: PMC3009178 PMID: 21588956

Abstract

In the title compound, C₂₈H₂₄O₄, the two 4-methylbenzoyl groups at the 1- and 8-positions of the naphthalene ring system are aligned almost antiparallel, the dihedral angle between the two phenyl rings being 9.64 (7)°. The dihedral angles between the two phenyl rings and the naphthalene ring system are 71.82 (6) and 71.58 (6)°. In the crystal, intermolecular C—H⋯O interactions between the carbonyl oxygen and aromatic hydrogen are observed.

Related literature

For the formation reaction of aroylated naphthalene compounds via electrophilic aromatic aroylation of 2,7-dimethoxynaphthalene, see: Okamoto & Yonezawa (2009 ▶). For related structures, see: Nakaema et al. (2007 ▶, 2008 ▶); Watanabe et al. (2010a ▶,b ▶).

Experimental

Crystal data

C₂₈H₂₄O₄
M _r = 424.47
Orthorhombic,
a = 20.0334 (3) Å
b = 13.4311 (2) Å
c = 7.94771 (10) Å
V = 2138.49 (5) Å³
Z = 4
Cu Kα radiation
μ = 0.70 mm⁻¹
T = 193 K
0.60 × 0.40 × 0.20 mm

Data collection

Rigaku R-AXIS RAPID diffractometer
Absorption correction: numerical (NUMABS; Higashi, 1999 ▶) T _min = 0.604, T _max = 0.873
33150 measured reflections
2110 independent reflections
2041 reflections with I > 2σ(I)
R _int = 0.034

Refinement

R[F ² > 2σ(F ²)] = 0.034
wR(F ²) = 0.094
S = 1.17
2110 reflections
293 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 0.18 e Å⁻³
Δρ_min = −0.17 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/S1600536810039620/om2367sup1.cif

e-66-o2752-sup1.cif^{(23.4KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810039620/om2367Isup2.hkl

e-66-o2752-Isup2.hkl^{(101.7KB, 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
C14—H14⋯O1ⁱ	0.95	2.52	3.465 (3)	175
C21—H21⋯O2ⁱⁱ	0.95	2.38	3.295 (3)	162

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

Acknowledgments

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

supplementary crystallographic information

Comment

In the course of our study on selective electrophilic aromatic aroylation of the naphthalene core, peri-aroylnaphthalene compounds have proved to be formed regioselectively by the aid of a suitable acidic mediator (Okamoto & Yonezawa, 2009). Recently, we reported the X-ray crystal structures of 1,8-diaroylated 2,7-dimethoxynaphthalene derivatives such as 1,8-bis(4-chlorobenzoyl)-2,7-dimethoxynaphthalene (Nakaema et al., 2007), 1,8-dibenzoyl-2,7-dimethoxynaphthalene (Nakaema et al., 2008), bis(4-bromophenyl)(2,7-dimethoxynaphthalene-1,8-diyl)dimethanone [1,8-bis(4-bromobenzoyl)-2,7-dimethoxynaphthalene] (Watanabe et al., 2010a) and (2,7-dimethoxynaphthalene-1,8-diyl)bis(4-fluorophenyl) dimethanone [1,8-bis(4-fluorobenzoyl)-2,7-dimethoxynaphthalene] (Watanabe et al., 2010b). The aroyl groups at 1,8-positions of the naphthalene rings in these compounds are oriented in opposite direction. The aromatic rings in the molecule are non-coplanar, resulting in partial disruption of π-conjugation of ring systems. As a part of our continuing studies on the molecular structures of this kind of homologous molecules, the X-ray crystal structure of title compound, peri-aroylnaphthalene bearing methyl groups, is discussed in this article.

The molecular structure of the title compound is displayed in Fig 1. Two 4-methylbenzoyl groups are situated in anti orientation and are twisted away from the attached naphthalene ring. The interplanar angle between the best planes of the two phenyl rings is 9.64 (7)°. On the other hand, the two interplanar angles between the best planes of the 4-methylphenyl rings and the naphthalene ring are 71.82 (6) and 71.58 (6)°, respectively. The torsion angles between the carbonyl groups and the naphthalene ring [C10—C1—C11—O1 = 68.1 (2)° and C10—C9—C18—O2 = 67.6 (2)°] are larger than those between the carbonyl groups and 4-methylphenyl groups [O1—C11—C12—C13 = -179.18 (15)° and O2—C18—C19—C20 = 176.67 (15)°]. In the molecular packing, the C—H···O hydrogen interactions between the oxygen atoms of the carbonyl groups and the hydrogen atoms of the phenyl rings are observed along the c axis [C14—H14···O1 = 2.52 Å and C21—H21···O2 = 2.38 Å] (Fig. 2).

Experimental

To a 30 ml flask, 4-methylbenzoic acid (8.00 mmol, 1.08 g) and phosphorus pentoxide–methanesulfonic acid mixture (P₂O₅–MsOH; 8.0 ml) were placed and stirred at 333 K. To the solution thus obtained, 2,7-dimethoxynaphthalene (4.00 mmol, 0.752 g) was added. After the reaction mixture was stirred at 333 K for 2 h, it was poured into ice-cold water (10 ml) and the mixture was extracted with CHCl₃ (10 ml × 3). The combined extracts were washed with 2 M aqueous NaOH followed by washing with brine. The organic layer was dried over anhydrous MgSO₄. The solvent was removed under reduced pressure to give a cake (57% yield). The crude product was purified by recrystallization from CHCl₃-hexane (isolated yield 35%). Furthermore, the isolated product was crystallized from EtOH to give single-crystals.

Spectral data:¹H NMR δ (300 MHz, CDCl₃): 2.37 (6H, s), 3.67 (6H, s), 7.11 (4H, d, J = 7.8 Hz), 7.19 (2H, d, J = 8.7 Hz), 7.57 (4H, d, J = 7.8 Hz), 7.92 (2H, d, J = 8.7 Hz). ¹³C NMR δ (300 MHz, CDCl₃): 21.740, 56.495, 111.34, 121.91, 125.58, 128.70, 129.25, 129.74, 131.79, 136.31, 143.17, 156.12, 196.22. IR (KBr): 1655 (C═O), 1607, 1512 (Ar, naphthalene). m.p. = 531.8–534.9 K. Anal. Calcd for C₂₈H₂₄O₄; C, 79.22; H, 5,70. Found C, 78.98; H, 5.78.