[2,7-Dimeth­oxy-8-(4-propyl­benzo­yl)naphthalen-1-yl](4-propyl­phen­yl)methanone

Kosuke Sasagawa; Daichi Hijikata; Rei Sakamoto; Akiko Okamoto; Noriyuki Yonezawa

doi:10.1107/S1600536812033582

. 2012 Jul 28;68(Pt 8):o2596. doi: 10.1107/S1600536812033582

[2,7-Dimethoxy-8-(4-propylbenzoyl)naphthalen-1-yl](4-propylphenyl)methanone

Kosuke Sasagawa ^a, Daichi Hijikata ^a, Rei Sakamoto ^a, Akiko Okamoto ^a,^*, Noriyuki Yonezawa ^a

PMCID: PMC3415032 PMID: 22905019

Abstract

In the title compound, C₃₂H₃₂O₄, the 4-propylbenzoyl groups at the 1- and 8-positions of the naphthalene ring system are aligned almost antiparallel, and their benzene rings make a dihedral angle of 8.64 (10)°. The dihedral angles between the naphthalene ring system and the benzene rings are 69.37 (8) and 69.45 (8)°. In the crystal, C—H⋯O interactions link adjacent molecules via their aroyl groups.

Related literature

For the formation reaction of aroylated naphthalene compounds via electrophilic aromatic substitution of naphthalene derivatives, see: Okamoto & Yonezawa (2009 ▶); Okamoto et al. (2011 ▶). For the structures of closely related compounds, see: Hijikata et al. (2010 ▶); Muto et al. (2010 ▶); Sasagawa, Hijikata et al. (2011) ▶; Sasagawa, Muto et al. (2011 ▶); Sasagawa et al. (2012 ▶).

Experimental

Crystal data

C₃₂H₃₂O₄
M _r = 480.58
Monoclinic,
a = 18.1224 (3) Å
b = 7.91914 (14) Å
c = 19.7355 (4) Å
β = 113.502 (1)°
V = 2597.37 (8) Å³
Z = 4
Cu Kα radiation
μ = 0.63 mm⁻¹
T = 193 K
0.40 × 0.30 × 0.05 mm

Data collection

Rigaku R-AXIS RAPID diffractometer
Absorption correction: numerical (NUMABS; Higashi, 1999 ▶) T _min = 0.786, T _max = 0.969
45013 measured reflections
4752 independent reflections
3258 reflections with I > 2σ(I)
R _int = 0.047

Refinement

R[F ² > 2σ(F ²)] = 0.048
wR(F ²) = 0.152
S = 1.10
4752 reflections
330 parameters
H-atom parameters constrained
Δρ_max = 0.22 e Å⁻³
Δρ_min = −0.26 e Å⁻³

Data collection: RAPID-AUTO (Rigaku, 1998 ▶); cell refinement: RAPID-AUTO; data reduction: RAPID-AUTO; program(s) used to solve structure: Il Milione (Burla et al., 2007) ▶; program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: CrystalStructure (Rigaku, 2010 ▶); software used to prepare material for publication: CrystalStructure.

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812033582/hb6909sup1.cif

e-68-o2596-sup1.cif^{(25.7KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812033582/hb6909Isup2.hkl

e-68-o2596-Isup2.hkl^{(228.1KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536812033582/hb6909Isup3.cml

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
C13—H13⋯O3ⁱ	0.95	2.41	3.342 (3)	168
C24—H24⋯O4ⁱⁱ	0.95	2.45	3.390 (3)	170

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

Acknowledgments

The authors express their gratitude to Master Toyokazu Muto, Department of Organic and Polymer Materials Chemistry, Graduate School, Tokyo University of Agriculture & Technology, and Professor Keiichi Noguchi, Instrumentation Analysis Center, Tokyo University of Agriculture and Technology, for their technical advice. This work was partially supported by a Sasagawa Scientific Research Grant from The Japan Science Society.

supplementary crystallographic information

Comment

In the course of our study on selective electrophilic aromatic aroylation of the naphthalene ring core, 1,8-diaroylnaphthalene compounds have proved to be formed regioselectively by the aid of a suitable acidic mediator (Okamoto & Yonezawa, 2009, Okamoto et al., 2011). Recently, we have reported the X-ray crystal structures of 1,8-diaroylated 2,7-dimethoxynaphthalene derivatives such as [2,7-dimethoxy-8-(4-methylbenzoyl)-1-naphthyl](4-methylphenyl)methanone [1,8-bis(4-methylbenzoyl)-2,7-dimethoxynaphthalene] (Muto et al., 2010), {8-[4-(bromomethyl)benzoyl]-2,7-dimethoxynaphthalen-1-yl}[4-(bromomethyl)phenyl]methanone [1,8-bis(4-bromomethylbenzoyl)-2,7-dimethoxynaphthalene] (Sasagawa, Hijikata et al., 2011), {8-[4-(butoxy)benzoyl]-2,7-dimethoxynaphthalen-1-yl}[4-(butoxy)phenyl]methanone [1,8-bis(4-butoxylbenzoyl)-2,7-dimethoxynaphthalene] (Sasagawa, Muto et al., 2011), and 4-{[8-(4-acetyloxybenzoyl)-2,7-dimethoxynaphthalen-1-yl]carbonyl}phenyl acetate [1,8-bis(4-acetoxybenzoyl)-2,7-dimethoxynaphthalene] (Sasagawa et al., 2012). The aroyl groups in these compounds are almost perpendicularly attached to the naphthalene rings and oriented in opposite directions (anti-orientation). Moreover, we have also shown that the aroyl groups of 2,7-dimethoxy-1,8-bis(4-phenoxybenzoyl)naphthalene (Hijikata et al., 2010) are oriented in same direction (syn-orientation). As part of our ongoing studies on the molecular structures of these kinds of homologous molecules, the X-ray crystal structure of the title compound, 1,8-diaroylated naphthalene bearing propyl groups, is discussed in this article.

The molecular structure of the title compound is displayed in Fig 1. Two 4-propylbenzoyl groups are situated in anti-orientation. The dihedral angle between the best planes of the two phenyl rings is 8.64 (10) °. The dihedral angles between the best planes of the 4-propylphenyl rings and the naphthalene ring are 69.37 (8) and 69.45 (8) °.

Ketonic carbonyl moieties (C11, O3; C21, O4), carbon atoms (C18; C28) of propyl groups and benzene ring are lie on the same plane [torsion angles O3—C11—C14—C12 = -179.58 (18)°, C18—C15—C17—C16 = 178.9 (2)°; O4—C21—C23—C25 = -178.18 (19)°, C28—C26—C27—C25 = -179.5 (2)°].

In the molecular packing, two types of C—H···O interactions between carbonyl oxygen atom and hydrogen atom of the benzene ring are observed (Fig. 2).

Experimental

To a 50 ml flask, 4-propylbenzoic acid (722 mg, 4.4 mmol), phosphorus pentoxide–methanesulfonic acid mixture (P₂O₅–MsOH [1/10 w/w]; 8.8 ml) were placed and stirred at 333 K. To the solution thus obtained, 2,7-dimethoxynaphthalene (376 mg, 2.0 mmol) was added. After the reaction mixture was stirred at 333 K for 1.5 h, it was poured into ice-cold water (10 ml). The aqueous layer 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 to give cake. The crude product was purified by recrystallization from methanol (54% yield). Colorless platelet single crystals were obtained by repeated crystallization from ethanol solution.

¹H-NMR δ (300 MHz, CDCl₃): 0.95 (6H, t, J = 7.2 Hz), 1.65 (4H, q, J = 7.2 Hz), 2.60 (4H, t, J =7.2 Hz), 3.69 (6H, s), 7.11 (4H, d, J = 7.5 Hz), 7.21 (2H, d, J = 8.7 Hz), 7.58 (4H, d, J = 7.5 Hz), 7.94 (2H, d, J = 9.0 Hz) p.p.m.

¹³C-NMR δ (75 MHz, CDCl₃): 13.9, 24.0, 38.2, 56.5, 111.3, 121.9, 125.5, 128.0, 129.2, 129.6, 131.8, 136.5, 147.8, 156.1, 196.2 p.p.m.

IR (KBr): 2952 (CH₃), 2927 (CH₂), 1656 (C=O), 1605, 1510, 1460 (Ar) cm^-1

HRMS (m/z): [M+H]⁺ calcd. for C₃₂H₃₃O₄,481.2379, found, 481.2421.

m.p. = 447.1—448.9 K