(3,6-Dimeth­oxy­naphthalen-2-yl)(naphthalen-2-yl)methanone

Takehiro Tsumuki; Shun Murohashi; Atsushi Nagasawa; Akiko Okamoto; Noriyuki Yonezawa

doi:10.1107/S1600536812034186

. 2012 Aug 8;68(Pt 9):o2653. doi: 10.1107/S1600536812034186

(3,6-Dimethoxynaphthalen-2-yl)(naphthalen-2-yl)methanone

Takehiro Tsumuki ^a, Shun Murohashi ^a, Atsushi Nagasawa ^a, Akiko Okamoto ^a,^*, Noriyuki Yonezawa ^a

PMCID: PMC3435680 PMID: 22969551

Abstract

In the title compound, C₂₃H₁₈O₃, the dihedral angle between the two naphthalene ring systems is 78.02 (3)°. The bridging carbonyl C—C(=O)—C plane makes a dihedral angle of 70.56 (5)° with the naphthalene ring system in the 2,7-dimethoxynaphthalene moiety and a dihedral angle of 11.53 (5)° with the naphthalene ring system in the naphthoyl group. In the crystal, adjacent molecules are linked via C—H⋯π interactions, forming chains along [010].

Related literature

For electrophilic aromatic aroylation of naphthalene derivatives, see: Okamoto & Yonezawa (2009 ▶); Okamoto et al. (2011 ▶). For the structures of closely related compounds, see: Kato et al. (2010 ▶, 2011 ▶); Nakaema et al. (2008 ▶); Tsumuki et al. (2011 ▶, 2012 ▶); Watanabe et al. (2010 ▶).

Experimental

Crystal data

C₂₃H₁₈O₃
M _r = 342.37
Monoclinic,
a = 13.4683 (9) Å
b = 8.9062 (5) Å
c = 14.7110 (8) Å
β = 105.646 (2)°
V = 1699.23 (17) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 193 K
0.60 × 0.30 × 0.20 mm

Data collection

Rigaku R-AXIS RAPID diffractometer
Absorption correction: numerical (NUMABS; Higashi, 1999 ▶) T _min = 0.941, T _max = 0.983
26536 measured reflections
3863 independent reflections
3436 reflections with I > 2σ(I)
R _int = 0.017

Refinement

R[F ² > 2σ(F ²)] = 0.038
wR(F ²) = 0.109
S = 1.06
3863 reflections
238 parameters
H-atom parameters constrained
Δρ_max = 0.31 e Å⁻³
Δρ_min = −0.18 e Å⁻³

Data collection: PROCESS-AUTO (Rigaku, 1998 ▶); cell refinement: PROCESS-AUTO; data reduction: PROCESS-AUTO; 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 datablock(s) I, global. DOI: 10.1107/S1600536812034186/su2487sup1.cif

e-68-o2653-sup1.cif^{(20.9KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812034186/su2487Isup2.hkl

e-68-o2653-Isup2.hkl^{(185.5KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536812034186/su2487Isup3.cml

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

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

Cg1 is the centroid of the C14–C19 ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C22—H22A⋯Cg4ⁱ	0.98	2.80	3.5470 (12)	133

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Symmetry code: (i) Inline graphic .

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 Iron and Steel Institute of Japan (ISIJ) Research Promotion Grant.

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 with the aid of suitable acidic mediator (Okamoto & Yonezawa, 2009; Okamoto et al., 2011). We have reported the structures of 1,8-dibenzoylnaphthalene analogues such as 1,8-dibenzoyl-2,7-dimethoxynaphthalene (Nakaema et al., 2008). The benzoyl groups at the 1,8-positions of the naphthalene rings in these compounds are bonded in a nearly perpendicular manner and orient in opposite directions. The 1-monobenzoylnaphthalene analogues, such as (2,7-dimethoxynaphthalen-1-yl)(phenyl)methanone (Kato et al., 2010), were also revealed to have essentially the same non-coplanar structure as observed for 1,8-dibenzoylated naphthalene analogues. The corresponding β-isomers of 3-monobenzoylated naphthalene analogues such as (3,6-dimethoxynaphthalen-2-yl)(phenyl)methanone (Kato, et al., 2011) and (4-fluorophenyl)(3,6-dimethoxy-2-naphthyl)methanone (Watanabe et al., 2010). In the 3-monobenzoylated naphthalene analogues, which are generally regarded to be thermodynamically more stable than the corresponding 1-positioned isomeric molecules, the aroyl groups are connected to the naphthalene rings in a moderately twisted fashion.

Recently, a series of the corresponding naphthoylated naphthalene homologues to the benzoylated naphthalenes have been reported, such as [2,7-dimethoxy-8-(2-naphthoyl)naphthalen-1-yl](naphthalen-2-yl)methanone (Tsumuki et al., 2011) and 1-(2-naphthoyl)-2,7-dimethoxynaphthalene (Tsumuki et al., 2012). As a part of our ongoing studies on the synthesis and structure of these homologous molecules, the crystal structure analysis of the title compound, a 2,7-dimethoxynaphthalene substituted at the 3-position by a 2-naphthoyl group, is reported on herein.

The molecular structure of the title molecule is illustrated in Fig. 1. The interplanar angle between the two naphthalene rings (C1—C10 and C12—C21) is 78.02 (3)°. The dihedral angle between the bridging carbonyl plane (O1—C3—C11—C12) and the naphthalene ring of the 2,7-demethoxynaphthalene moiety (C1—C10) is larger than that between the bridging carbonyl plane (O1—C3—C11—C12) and naphthalene ring of the naphthoyl group (C12—C21) [70.56 (5)° versus. 11.53 (5)°; torsion angle C2—C3—C11—O1 = -110.65 (13)° versus. torsion angle O1—C11—C12—C13 = -167.08 (11)°]

In the crystal, neighbouring molecules are linked by C—H···π interactions along the b axis (Table 1 and Fig. 2).

Experimental

The title compound was prepared by treatment of a mixture of 2,7-dimethoxynaphthalene (188 mg, 1 mmol) and 2-naphthoic acid (189 mg, 1.1 mmol) with phosphorus pentoxide—methanesulfonic acid mixture (P₂O₅—MsOH [1/10 w/w] 2.2 ml). After the reaction mixture had been stirred at 333 K for 6 h, the mixture was poured into ice-cold water and extracted with CHCl₃ (3 × 10 ml). The combined extracts were washed with 2 M aqueous NaOH (3 × 15 ml) followed by washing with brine ( 3 × 15 ml). The organic layer thus obtained was dried over anhydrous MgSO₄. The solvent was removed under reduced pressure to give a cake (yield 349 mg, quant.). The crude product was purified by flush silica gel chromatography (eluent: toluene; isolated yield 28%). Colourless platelet single crystals suitable for X-ray diffraction were obtained by crystallization from chloroform. Spectroscopic data for the title compound are given in the archived CIF.