(2,7-Dimeth­oxy­naphthalen-1-yl)(phen­yl)methanone

Yuichi Kato; Atsushi Nagasawa; Daichi Hijikata; Akiko Okamoto; Noriyuki Yonezawa

doi:10.1107/S1600536810038195

. 2010 Sep 30;66(Pt 10):o2659. doi: 10.1107/S1600536810038195

(2,7-Dimethoxynaphthalen-1-yl)(phenyl)methanone

Yuichi Kato ^a, Atsushi Nagasawa ^a, Daichi Hijikata ^a, Akiko Okamoto ^a, Noriyuki Yonezawa ^a,^*

PMCID: PMC2983196 PMID: 21587630

Abstract

The asymmetric unit of the title compound, C₁₉H₁₆O₃, contains three independent conformers. Each of the three conformers has essentially the same feature of non-coplanar aromatic rings whereby the aroyl group at the 1-position of the naphthalene ring is twisted in a perpendicular manner to the naphthalene ring. The dihedral angles between the benzene ring planes and the naphthalene ring systems are 75.34 (7), 86.47 (7) and 76.55 (6)° in the three conformers. The crystal structure is stabilized by intermolecular C—H⋯O hydrogen bonds.

Related literature

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

Experimental

Crystal data

C₁₉H₁₆O₃
M _r = 292.32
Monoclinic,
a = 23.4356 (4) Å
b = 7.84115 (14) Å
c = 26.7438 (5) Å
β = 111.786 (1)°
V = 4563.49 (14) Å³
Z = 12
Cu Kα radiation
μ = 0.69 mm⁻¹
T = 193 K
0.60 × 0.20 × 0.10 mm

Data collection

Rigaku R-AXIS RAPID diffractometer
Absorption correction: numerical (NUMABS; Higashi, 1999 ▶) T _min = 0.682, T _max = 0.934
76914 measured reflections
8353 independent reflections
6698 reflections with I > 2σ(I)
R _int = 0.021

Refinement

R[F ² > 2σ(F ²)] = 0.039
wR(F ²) = 0.109
S = 1.12
8353 reflections
602 parameters
H-atom parameters constrained
Δρ_max = 0.22 e Å⁻³
Δρ_min = −0.16 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: CrystalStructure.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810038195/om2366sup1.cif

e-66-o2659-sup1.cif^{(36.5KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810038195/om2366Isup2.hkl

e-66-o2659-Isup2.hkl^{(400.4KB, 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
C36—H36⋯O2	0.95	2.56	3.4116 (18)	149
C56—H56A⋯O5ⁱ	0.98	2.54	3.4862 (19)	161
C52—H52⋯O3ⁱ	0.95	2.46	3.395 (2)	168
C34—H34⋯O6ⁱⁱ	0.95	2.41	3.143 (2)	133
C54—H54⋯O9ⁱⁱ	0.95	2.58	3.2451 (19)	128
C19—H19B⋯O9ⁱⁱⁱ	0.98	2.59	3.116 (2)	113

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

Acknowledgments

The authors would express their gratitude to Professor Keiichi Noguchi for technical advice. This work partly was supported by a Sasagawa Scientific Research Grant from the Japan Science Society.

supplementary crystallographic information

Comment

In the course of our study on electrophilic aromatic aroylation of 2,7-dimethoxynaphthalene, peri-aroylnaphthalene compounds have proven to be formed regioselectively with the aid of suitable acidic mediators (Okamoto & Yonezawa, 2009). Recently, we reported the crystal structures of several 1,8-diaroylated naphthalene homologues exemplified by (2,7-dimethoxynaphthalene-1,8-diyl)bis(4-fluorobenzoyl)dimethanone (Watanabe et al., 2010). The aroyl groups at the 1,8-positions of the naphthalene rings in these compounds are connected almost perpendicularly but the benzene ring moieties of the aroyl groups tilt slightly toward the exo sides of the naphthalene rings. In the crystal of 1,8-dibenzoyl-2,7-dimethoxynaphthalene (Nakaema et al., 2008), molecules are arranged by C–H···O hydrogen bonding along the c axis of the unit cell, and a π–π stacking interaction perpendicular to the bc plane is also observed. Moreover, the X-ray crystal structural analyses of 1-(4-substituted benzoyl)naphthalenes, i.e., 1-(4-chlorobenzoyl)-2,7-dimethoxynaphthalene (Mitsui et al., 2008), 2-(2,7-dimethoxy-1-naphthoyl)benzoic acid (Hijikata et al.., 2010a) and methyl 4-(2,7-dimethoxy-1-naphthoyl)benzoate (Hijikata et al., 2010b), have also revealed to have essentially the same non-coplanar structure with the 1,8-diaroylated naphthalenes. As a part of the course of our continuous study on the molecular structures of this kind of homologous molecules, the crystal structure of title compound, 1-benzoylatednaphthalene, is discussed in this paper.

There are three independent conformers in the crystal structure of the title compound. The independent conformers are labeled (A), (B), and (C) and are shown in Fig. 1. Each conformer has essentially the same non-coplanar structure. The respective dihedral angles between the naphthalene rings and the benzene rings of the three conformers are 75.34 (7), 86.46 (7), and 76.55 (6)°. The bridging carbonyl planes make large dihedral angles of 77.57 (7)° [C2—C1—C11—O3 torsion angle = -77.82 (18)°], 88.38 (7)° [C21—C20—C30—O6 torsion angle = -90.52 (18)°], and 81.87 (7)° [C40—C39—C49—O9 torsion angle = -101.94 (17)°] with the naphthalene ring systems. On the other hand, the dihedral angles between the bridging carbonyl planes and the benzene rings are rather small, such as 8.27 (9)° [O3—C11—C12—C17 torsion angle = -173.33 (14)°], 10.23 (9)° [O6—C30—C31—C36 torsion angle = -170.51 (15)°], and 15.95 (8)° [O9—C49—C50—C55 torsion angle = 167.01 (14)°]. The methyl groups of the methoxy groups adjacent to the aroyl groups, are oriented to the exo sites of the molecules and the other methyl groups are directed to endo sites. The crystal structure is stabilized by intermolecular hydrogen bonds among three different conformers and between same types of conformers (Table 1, Fig. 2, 3). Among three different conformers, hydrogen bonds between conformers (A) and (B) [C36–H36···O2= 2.564 Å], between conformers (B) and (C) [C56—H56A···O5 = 2.544 Å], and between conformers (C) and (A) [C52—H52···O3 = 2.460 Å] are observed. In addition, the conformers (B) are connected to each other by intermolecular hydrogen bonds between carbonyl oxygen and aromatic hydrogen [C34–H34···O6 = 2.413 Å].The conformers (C) are also linked with intermolecular hydrogen bonds between carbonyl oxygen and aromatic hydrogen [C54–H54···O9 = 2.576 Å]. The conformers (B) and (C) are stacked along the b axis and form the columnar structures, respectively. On the other hand, the conformers (A) have no interactions with themselves along the b axis. They have only weak intermolecular interactions with conformers (C) [C19–H19B···O9 = 2.593 Å] and are piled in the gap of the two different columnar structures of conformers (B) and (C) (Fig. 4).

Experimental

To a 100 ml flask, benzoyl chloride (8.1 mmol, 0.923 ml), aluminium chloride (AlCl₃; 10.4 mmo1, 1.38 g) and methylene chloride (CH₂Cl₂; 19 ml) were placed and stirred at 273 K. To the reaction mixture thus obtained 2,7-dimethoxynaphthalene (7.5 mmol, 1.372 g) in methylene chloride (CH₂Cl₂; 19 ml) were added. After the reactionmixture was stirred at 273 K for 6 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 layers thus obtained were dried over anhydrous MgSO₄. The solvent was removed under reduced pressure togive a cake (98% yield). The crude product was purified by recrystallization from hexane-chloroform. Yellow platelet single-crystals suitable for X-ray diffraction were obtained by crystallization from hexane-methylene chloride.

Spectroscopic Data:

¹H NMR δ (300 MHz, CDCl₃); 3.71 (3H, s), 3.78 (3H, s, J = 8.6 Hz), 6.79 (1H, d, J = 2.4 Hz), 7.01 (1H, dd, J = 8.7, 2.4 Hz), 7.16 (1H, d, J = 9.0 Hz), 7.43 (2H, t, J = 7.8 Hz), 7.57 (1H, t, J = 7.2 Hz), 7.72 (1H, d, J = 8.7 Hz), 7.72 (1H, d, J = 8.7 Hz), 7.84–7.89 (3H, m) p.p.m..

¹³C NMR δ (300 MHz, CDCl₃); 55.09, 56.24, 102.02, 110.17, 117.01, 121.67,124.29, 128.48, 129.44, 129.62, 130.96, 132.98, 133.31, 137.98, 154.93, 158.77,198.07 p.p.m..

IR(KBr):1663.30 (C=O), 1626.66 (Ar) cm^-1.

HRMS(m/z): [M + H]⁺ Calcd for C₁₉H₁₇O₃, 293.3365; found, 293.1185.

m.p.= 358.5–362 K