Methyl 4-(2,7-dimeth­oxy-1-naphtho­yl)benzoate

Daichi Hijikata; Kosuke Nakaema; Shoji Watanabe; Akiko Okamoto; Noriyuki Yonezawa

doi:10.1107/S160053681000382X

. 2010 Feb 6;66(Pt 3):o554. doi: 10.1107/S160053681000382X

Methyl 4-(2,7-dimethoxy-1-naphthoyl)benzoate

Daichi Hijikata ^a, Kosuke Nakaema ^a, Shoji Watanabe ^a, Akiko Okamoto ^a, Noriyuki Yonezawa ^a,^*

PMCID: PMC2983753 PMID: 21580323

Abstract

In the title compound, C₂₁H₁₈O₅, the dihedral angle between the naphthalene ring system and the benzene ring is 86.65 (6)°. The bridging carbonyl C—C(=O)—C plane makes dihedral angles of 83.57 (7) and 20.21 (8)°, respectively, with the naphthalene ring system and the benzene ring. The ester O—C=O plane and the benzene ring are almost coplanar, making a dihedral angle of 3.81 (18)°. The two methoxy groups lie essentially in the naphthalene ring plane [C—O—C—C torsion angles = 2.1 (2) and −1.44 (19)°]. In the crystal structure, a centrosymmetric dimer is formed through C—H⋯O bonds connecting the 7-methoxy group and the carbonyl O atom of the ester group. The dimers are further linked by C—H⋯O hydrogen bonds between the methoxycarbonyl group and the bridging carbonyl O atom.

Related literature

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

Experimental

Crystal data

C₂₁H₁₈O₅
M _r = 350.35
Triclinic,
a = 7.7714 (2) Å
b = 9.5195 (3) Å
c = 12.2737 (4) Å
α = 97.525 (2)°
β = 97.919 (2)°
γ = 106.630 (2)°
V = 847.73 (5) Å³
Z = 2
Cu Kα radiation
μ = 0.81 mm⁻¹
T = 193 K
0.40 × 0.20 × 0.05 mm

Data collection

Rigaku R-AXIS RAPID diffractometer
Absorption correction: numerical (NUMABS; Higashi, 1999 ▶) T _min = 0.816, T _max = 0.960
15482 measured reflections
3066 independent reflections
2571 reflections with I > 2σ(I)
R _int = 0.029

Refinement

R[F ² > 2σ(F ²)] = 0.037
wR(F ²) = 0.117
S = 1.08
3066 reflections
239 parameters
H-atom parameters constrained
Δρ_max = 0.24 e Å⁻³
Δρ_min = −0.20 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 global, I. DOI: 10.1107/S160053681000382X/is2518sup1.cif

e-66-0o554-sup1.cif^{(20.7KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S160053681000382X/is2518Isup2.hkl

e-66-0o554-Isup2.hkl^{(147.4KB, 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
C19—H19B⋯O2ⁱ	0.98	2.57	3.461 (2)	152
C21—H21A⋯O1ⁱⁱ	0.98	2.49	3.4446 (19)	163

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

Acknowledgments

The authors would express their gratitude to Professor Keiichi Noguchi for technical advice. This work was partially supported by the Iketani Science and Technology Foundation, Tokyo, Japan.

supplementary crystallographic information

Comment

In the course of our study 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). The aroyl groups at 1,8-positions of the naphthalene rings in these compounds are twisted almost perpendicularly but a little tiltedly toward exo sides against the naphthalene ring.

Recently, we have reported the X-ray crystal structures of several 1,8-diaroylated naphthalene homologues exemplified by bis(4-bromobenzoyl)(2,7-dimethoxynaphthalene-1,8-diyl)dimethanone (Watanabe et al., 2010). Furthermore, we have also clarified the crystal structures of 1-monoaroylated naphthalenes. 1-(4-Chlorobenzoyl)-2,7-dimethoxynaphthalene (Mitsui, Nakaema, Noguchi, Okamoto & Yonezawa, 2008) and (4-chlorobenzoyl)(2-ethoxy-7-methoxynaphthalen-1-yl)methanone (Mitsui et al., 2009) have essentially same non-coplanar structure as 1,8-diaroylated naphthalenes, and (4-chlorophenyl)(2-hydroxy-7-methoxynaphthalen-1-yl)methanone has substantially coplanar structure by intramolecular hydrogen bonding (Mitsui, Nakaema, Noguchi & Yonezawa, 2008). As a part of the course of our continuous study on the molecular structures of this kind of homologous molecules, the X-ray crystal structure of title compound, 1-monoaroylnaphthalene bearing ester group, is discussed in this report.

An ORTEPIII (Burnett & Johnson, 1996) plot of (I) is displayed in Fig. 1. In the molecule of (I), the interplanar angle between the benzene ring (C12—C17) and the naphthalene ring (C1—C10) is 86.65 (6)°. The dihedral angle between the ketonic C=O plane and the naphthalene ring is 83.57 (7)° [C10—C1—C11—O1 torsion angle = 84.41 (18)°]. The dihedral angle between the ketonic C=O plane and the benzene ring is 20.21 (8)° [C17—C12—C11—O1 torsion angle = 19.9 (2)°]. The torsion angle between the ketonic carbonyl group and benzene ring [C17—C12—C11—O1 torsion angle = 19.9 (2)°] is larger than that between the carbonyl moiety of ester group and the benzene ring [C14—C15—C20—O2 torsion angle = -4.0 (2)°]. Two methoxy groups lie essentially on the naphthalene ring plane. The methyl group on O4, which is a part of methoxy group adjacent to the aroyl group, is oriented to the exo site of the molecule and that on O5 is directed to endo site. In the crystal packing, molecules are aligned forming dimeric pairs. Each pair has two intermolecular C—H···O bonds therein: equivalent hydrogen bonds between a H atom of 7-methoxy group (H19B) and the O atom of carbonyl moiety in ester group (O2). There is another type of hydrogen bond between dimeric pairs: hydrogen bonds between a H atom of the methyl moiety in ester group (H21A) and the O atom of ketonic carbonyl group (O1) (Fig. 2 and Table 1).

Experimental

The title compound was prepared by regioselective electrophilic aromatic aroylation of 2,7-dimethoxynaphthalene with 4-(bromomethyl)benzoyl chloride followed by transformation of bromomethyl group. Single crystals suitable for X-ray diffraction were obtained by recrystallization from ethanol.

Spectroscopic Data: ¹H NMR (300 MHz, CDCl₃): δ3.73 (3H, s), 3.76 (3H, s), 3.94 (3H, s), 6.83 (1H, s), 7.01 (1H, d, J = 9.0 Hz), 7.14 (1H, d, J = 9.0 Hz), 7.71 (1H, d, J = 9.0 Hz), 7.87–7.90 (3H, m), 8.07 (2H, d, J = 8.1 Hz); ¹³C NMR (75.0 MHz, CDCl₃): δ52.4, 55.2, 56.2, 101.9, 110.1, 117.2, 121.0, 124.4, 129.2, 129.7, 129.8, 131.6, 133.0, 133.9, 141.6, 155.4, 159.1, 166.4, 197.5; IR (KBr): 1674, 1625, 1511; m.p. = 154.6–157.1 °C; Anal. Calcd for C₂₁H₁₈O₅: C 71.99, H 5.18%. Found: C 72.05, H 5.25%.