(4-Chloro­benzoyl)(2-eth­oxy-7-methoxy­naphthalen-1-yl)methanone

Ryosuke Mitsui; Keiichi Noguchi; Noriyuki Yonezawa

doi:10.1107/S1600536809004796

. 2009 Feb 18;65(Pt 3):o543. doi: 10.1107/S1600536809004796

(4-Chlorobenzoyl)(2-ethoxy-7-methoxynaphthalen-1-yl)methanone

Ryosuke Mitsui ^a, Keiichi Noguchi ^b, Noriyuki Yonezawa ^a,^*

PMCID: PMC2968497 PMID: 21582202

Abstract

In the title compound, C₂₀H₁₇ClO₃, the naphthalene and benzene rings form an interplanar angle of 83.30 (8)°. The conformation around the central C=O group is such that the C=O bond vector forms a larger angle to the plane of the naphthalene ring than to the plane of the benzene ring, viz. 55.8 (2)° versus 15.8 (2)°. The 4-chlorophenyl groups form a centrosymmetric π–π interaction, with a centroid–centroid distance of 3.829 (1) Å and a lateral offset of 1.758 Å. An intermolecular C—H⋯O interaction is formed between the 4-chlorophenyl group and the O atom of a neighbouring methoxy group, and two very weak C—H⋯π contacts are present.

Related literature

For structures of closely related compounds, see: Mitsui, Nakaema, Noguchi, Okamoto & Yonezawa (2008 ▶); Mitsui, Nakaema, Noguchi & Yonezawa (2008 ▶).

Experimental

Crystal data

C₂₀H₁₇ClO₃
M _r = 340.79
Monoclinic,
a = 7.26434 (13) Å
b = 20.8849 (4) Å
c = 12.2094 (2) Å
β = 113.201 (1)°
V = 1702.55 (5) Å³
Z = 4
Cu Kα radiation
μ = 2.11 mm⁻¹
T = 193 K
0.40 × 0.30 × 0.20 mm

Data collection

Rigaku R-AXIS RAPID diffractometer
Absorption correction: numerical (NUMABS; Higashi, 1999 ▶) T _min = 0.542, T _max = 0.656
30947 measured reflections
3104 independent reflections
2544 reflections with I > 2σ(I)
R _int = 0.023

Refinement

R[F ² > 2σ(F ²)] = 0.041
wR(F ²) = 0.120
S = 1.10
3104 reflections
218 parameters
23 restraints
H-atom parameters constrained
Δρ_max = 0.27 e Å⁻³
Δρ_min = −0.28 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/S1600536809004796/bi2344sup1.cif

e-65-0o543-sup1.cif^{(19.8KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809004796/bi2344Isup2.hkl

e-65-0o543-Isup2.hkl^{(149.2KB, 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
C20—H20B⋯Cg1ⁱ	0.98	3.02	3.821 (3)	140
C20—H20C⋯Cg1ⁱⁱ	0.98	3.01	3.477 (3)	110
C13—H13⋯O3ⁱⁱⁱ	0.95	2.44	3.213 (2)	138

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) . Cg1 is the centroid of the C1–C5/C10 ring.

Acknowledgments

This work was financially supported by Seiki Kogyo Co Ltd, Tokorozawa, Saitama, Japan.

supplementary crystallographic information

Comment

Recently, we have reported the crystal structures of 1-(4-chlorobenzoyl)-2,7-dimethoxynaphthalene and (4-chlorophenyl)(2-hydroxy-7-methoxynaphthalen-1-yl)methanone (Mitsui, Nakaema, Noguchi, Okamoto & Yonezawa, 2008; Mitsui, Nakaema, Noguchi & Yonezawa, 2008). As a part of our ongoing studies on the synthesis and crystal structure analyses of aroylated naphthalene derivatives, this paper reports the crystal structure of the title compound, prepared by ethylation of (4-chlorophenyl)(2-hydroxy-7-methoxynaphthalen-1-yl)methanone with ethyl iodide.

In the molecule (Fig. 1), the interplanar angle between the benzene ring [C12–C17] and the naphthalene ring [C1–C10] is 83.30 (8)°. The C=O bond vector lies close to the mean plane of the benzene ring (angle 15.8 (2)°), but forms an angle of 55.77 (15)° to the plane of the naphthalene ring. The conformation of these groups is similar to 1-(4-chlorobenzoyl)-2,7-dimethoxynaphthalene. On the other hand, the methoxy group is arranged toward the aroyl group [C20—O3—C8—C7 torsion angle = 177.7 (2)°] while that of the aforementioned related compound is arranged toward the naphthalene ring [-7.1 (3)°]. In both compounds, the C—O bond vector of the methoxy group lies approximately in the plane of the naphthalene ring [angle 4.2 (1)° in the title compound, 5.05 (9)° in the related compound].

In the crystal structure, the naphthalene rings interact with ethyl groups [C7···H18A = 2.87 Å, C7···H18B = 2.88 Å] and methyl groups [C5···H20B = 2.75 Å] of the adjacent molecule along the a axis (Fig. 2). The neighboring inversion-related ethyl groups interact with each other [H19C···H19C = 2.39 Å] along the c axis. The C=O groups interact with benzene rings [O1···H17 = 2.66 Å] along the b axis (Fig. 3). Adjacent 4-chlorophenyl groups related by crystallographic inversion centers are exactly antiparallel and the perpendicular distance between the mean planes of these groups is 3.402 (1) Å (Fig. 4). The centroid–centroid distance between the two antiparallel phenyl rings is 3.829 (1) Å and the lateral offset is 1.758 Å, indicating the presence of a π–π interaction. Moreover, molecules are linked by C—H···π interactions. The methyl group acts as a hydrogen-bond donor and the π system of the naphthalene ring [C1/C2/C3/C4/C5/C10 ring (with centroid Cg1)] of an adjacent molecule acts as an acceptor, viz. C20—H20B···π, C20—H20C···π (Fig. 2 and Table 1). Intermolecular C—H···O hydrogen bonds between the methoxy O and an H atom of the 4-chlorophenyl group of the adjacent molecule are also found along the c axis (C13—H13···O3ⁱ; Fig. 2 and Table 1).

Experimental

(4-Chlorophenyl)(2-hydroxy-7-methoxynaphthalen-1-yl)methanone (0.13 g, 0.40 mmol) was dissolved in acetone (1.0 ml) and aqueous 0.8M NaOH (1.0 ml). EtI (0.31 g, 2.0 mmol) was added and the reaction mixture was heated at reflux for 6 h. Upon cooling to ambient temperature, the mixture was poured into H₂O (5 ml) and CHCl₃ (5 ml), and the aqueous layer was extracted with CHCl₃ (3 × 5 ml). The combined organic layers were washed with brine (3 × 20 ml), and dried over MgSO₄ overnight. The solvent was removed in vacuo and the crude material was purified by recrystallization from hexanes to give the title compound as colorless blocks (m.p. 365.5–366.0 K, yield 95 mg, 70%).

Spectroscopic Data: ¹H NMR (300 MHz, CDCl₃) δ 7.83 (d, 1H), 7.77 (d, 2H), 7.70 (d, 1H), 7.38 (d, 2H), 7.11 (d, 1H), 7.02 (dd, 1H), 6.86 (d, 1H), 4.05 (q, 2H), 3.74 (s, 3H), 1.10 (s, 3H); ¹³C NMR (75 MHz, CDCl₃) δ 196.8, 159.1, 154.8, 139.4, 137.1, 133.2, 131.3, 130.7, 129.7, 128.7, 124.5, 121.7, 117.2, 111.5, 102.3, 65.0, 55.2, 14.6; IR (KBr): 1671, 1624, 1582, 1511, 1464, 1249, 1227, 1046; HRMS (m/z): [M + H]⁺ calcd for C₂₀H₁₈ClO₃, 341.0945; found, 341.0903.