2-(1H-Benzimidazol-1-yl)-1-(2-furyl)ethanone O-propyloxime

Özden Özel Güven; Taner Erdoğan; Simon J Coles; Tuncer Hökelek

doi:10.1107/S1600536809020844

. 2009 Jun 6;65(Pt 7):o1517–o1518. doi: 10.1107/S1600536809020844

2-(1H-Benzimidazol-1-yl)-1-(2-furyl)ethanone O-propyloxime

Özden Özel Güven ^a, Taner Erdoğan ^a, Simon J Coles ^b, Tuncer Hökelek ^c,^*

PMCID: PMC2969417 PMID: 21582809

Abstract

In the molecule of the title compound, C₁₆H₁₇N₃O₂, the planar benzimidazole ring system [maximum deviation = 0.013 (1) Å] is oriented at a dihedral angle of 75.32 (4)° with respect to the furan ring. An intramolecular C—H⋯O interaction results in the formation of a planar six-membered ring [maximum deviation = 0.019 (15) Å], which is oriented at a dihedral angle of 1.91 (3)° with respect to the adjacent furan ring. In the crystal structure, intermolecular C—H⋯N interactions link the molecules into centrosymmetric R ₂ ²(18) dimers. In addition, the structure is stabilized by π–π contacts between the imidazole rings [centroid–centroid distance = 3.5307 (8) Å] and weak C—H⋯π interactions.

Related literature

Several compounds containing an oxime or an oxime ether function have been reported to exhibit antimicrobial activity, see: Baji et al. (1995 ▶); Bhandari et al. (2009 ▶); Emami et al. (2002 ▶, 2004 ▶); Milanese et al. (2007 ▶); Polak (1982 ▶); Poretta et al. (1993 ▶); Ramalingan et al. (2006 ▶); Rosello et al. (2002 ▶). For related structures, see: Özel Güven et al. (2007a ▶,b ▶). For ring motifs, see: Bernstein et al. (1995 ▶).

Experimental

Crystal data

C₁₆H₁₇N₃O₂
M _r = 283.33
Monoclinic,
a = 8.4164 (2) Å
b = 18.2524 (3) Å
c = 10.2246 (2) Å
β = 111.354 (1)°
V = 1462.87 (5) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 120 K
0.50 × 0.35 × 0.35 mm

Data collection

Bruker–Nonius Kappa CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2007 ▶) T _min = 0.958, T _max = 0.960
19714 measured reflections
3344 independent reflections
2755 reflections with I > 2σ(I)
R _int = 0.038

Refinement

R[F ² > 2σ(F ²)] = 0.043
wR(F ²) = 0.114
S = 1.14
3344 reflections
259 parameters
All H-atom parameters refined
Δρ_max = 0.37 e Å⁻³
Δρ_min = −0.36 e Å⁻³

Data collection: COLLECT (Hooft, 1998 ▶); cell refinement: DENZO (Otwinowski & Minor, 1997 ▶) and COLLECT; data reduction: DENZO nd COLLECT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶) and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809020844/ci2817sup1.cif

e-65-o1517-sup1.cif^{(19.7KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809020844/ci2817Isup2.hkl

e-65-o1517-Isup2.hkl^{(160.7KB, 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
C11—H11⋯O2	0.97 (2)	2.359 (16)	2.7930 (17)	106 (1)
C13—H13⋯N2ⁱ	0.96 (2)	2.360 (15)	3.2872 (17)	162 (1)
C14—H141⋯Cg1ⁱⁱ	0.99 (2)	2.968 (17)	3.8346 (16)	146 (1)
C16—H161⋯Cg2ⁱⁱ	0.99 (2)	2.685 (18)	3.5644 (16)	148 (1)
C16—H163⋯Cg3ⁱⁱ	1.00 (2)	2.643 (18)	3.5901 (15)	157 (1)

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Symmetry codes: (i) Inline graphic ; (ii) . Cg1, Cg2 and Cg3 are the centroids of the C2–C7, N1/N2/C1/C2/C7 and O1/C10–C13 rings, respectively.

Acknowledgments

The authors acknowledge the Zonguldak Karaelmas University Research Fund (Project No. 2007/2–13-02–09).

supplementary crystallographic information

Comment

Oxiconazole (Polak, 1982) is a well known antifungal agent with a broad spectrum of activity, used for the treatment of skin mycoses. It is structurally characterized by an oxime ether group. Several compounds containing an oxime or an oxime ether function have been reported to exhibit antimicrobial activity (Poretta et al., 1993; Baji et al., 1995; Rosello et al., 2002; Emami et al., 2002; Emami et al., 2004; Ramalingan et al., 2006; Milanese et al., 2007; Bhandari et al., 2009). In our earlier studies, we reported the crystal structure of a benzimidazole substituted oxiconazole derivative (Özel Güven et al., 2007a). Now, we report herein the crystal structure of the title alkyl oxime ether.

In the molecule of the title compound (Fig. 1), the bond lengths and angles are generally within normal ranges. The planar benzimidazole ring system is oriented with respect to the furan ring at a dihedral angle of 75.32 (4)°. Atoms O2, N3, C8, C9, C14 and C15 are 0.073 (1), 0.024 (1), -0.064 (1), -0.009 (1), 0.088 (1) and -0.082 (1) Å away from the furan ring plane, respectively, while atom C8 is at a distance of -0.007 (1) Å to the benzimidazole ring plane. So, they are coplanar with the adjacent rings. The N1—C1—N2 [114.29 (11)°], N2—C2—C7 [110.24 (11)°] and C2—C7—C6 [122.57 (11)°] bond angles are enlarged, while C5—C6—C7 [116.36 (11)°] and C2—C3—C4 [117.87 (11)°] bond angles are narrowed. An intramolecular C—H···O interaction (Table 1) results in the formation of a planar six-membered ring, (O2/N3/C9—C11/H11), which is oriented with respect to the adjacent furan ring at a dihedral angle of 1.91 (3)°. So, they are almost coplanar.

In the crystal structure, intermolecular C—H···N interactions (Table 1) link the molecules into centrosymmetric dimers through R₂²(18) ring motifs (Bernstein et al., 1995) (Fig. 2), in which they may be effective in the stabilization of the structure. The π···π contact between the benzimidazole rings [Cg2···Cg2ⁱ = 3.5307 (8) Å, where Cg1 is centroid of the N1/N2/C1/C2/C7 ring; symmetry code: (i) 2 - x, 1 -y, 2 - z] may further stabilize the structure. There also exist three weak C—H···π interactions (Table 1).

Experimental

The title compound was synthesized by the reaction of 2-(1H-benzimidazol-1-yl)-1-(furan-2-yl)ethanone oxime obtained from 2-(1H-benzimidazol-1-yl)-1-(furan-2-yl)ethanone (Özel Güven et al., 2007b) with n-propyl bromide and NaH. To a solution of 2-(1H-benzimidazol-1-yl)-1-(furan-2-yl)ethanone oxime (350 mg, 1.451 mmol) in DMF (5 ml) was added NaH (58 mg, 1.451 mmol) in small fractions. Then, n-propyl bromide (178 mg, 1.451 mmol) was added dropwise. The mixture was stirred at room temperature for 3 h and the excess of hydride was decomposed with a small amount of methyl alcohol. After evaporation to dryness under reduced pressure, the crude residue was suspended with water and extracted with methylene chloride. The organic layer was dried over anhydrous sodium sulfate and then evaporated to dryness. The crude product was purified by chromatography on a silica-gel column using chloroform and recrystallized from hexane-ethyl acetate (1:3) mixture to obtain pale-yellowish crystals (yield 150 mg, 37%).