4-[3-(2H-Benzotriazol-2-yl)propoxy]-3-methoxybenzaldehyde

In the title compound, C17H17N3O3, the 3-methoxybenzaldehyde group and the benzotriazole fragment are connected through a flexible oxypropyl chain. The O—C—C—C torsion angle in the central link is −63.9 (2)°, while the plane of the benzene ring of the 3-methoxybenzaldehyde substituent forms a dihedral angle of 56.4 (4)° with the benzotriazole plane.

In the title compound, C 17 H 17 N 3 O 3 , the 3-methoxybenzaldehyde group and the benzotriazole fragment are connected through a flexible oxypropyl chain. The O-C-C-C torsion angle in the central link is À63.9 (2) , while the plane of the benzene ring of the 3-methoxybenzaldehyde substituent forms a dihedral angle of 56.4 (4) with the benzotriazole plane.

Comment
The incorporation of azole nucleus is an important synthetic strategy in drug discovery. The high therapeutic properties of the related drugs have encouraged the medicinal chemists to synthesize large number of novel chemotherapeutic agents.
1H-Benzotriazole and many of its derivatives exhibit important biological properties, some are showing anti-inflammatory, antiviral, antifungal, antineoplastic and antidepressant activities (Al-Soud et al., 2003;Nanjunda Swamy et al., 2006). Recently, the structure of aralkyl nitroimidazole ether, which shows inhibitory effects on several types of pathogenic bacteria, has been published (Khalafi-Nezhad et al., 2005;Jin et al., 2009). Taking into account promising therapeutic applications of benzotriazole derivatives, we are focusing on the development of new drugs belonging to this class. Herein we report the crystal structure of the title compound (Fig. 1).
The 3-methoxybenzaldehyde group and benzotriazole fragment in the molecule of the title compound are connected through the flexible oxypropyl chain. The O3-C9-C10-C11 torsion angle in the central link is equal to -63.9 (2)°, whereas the planes of the benzene ring C2-C7 and benzotriazole system N1-N3, C12-C17 form the dihedral angle of 56.4 (4)°.

Experimental
A solution of benzotriazole (0.119 g, 1 mmol), 4-(3-bromopropoxy)-3-methoxy benzaldehyde (0.273 g, 1 mmol) and triethyl amine (1.01 g, 0.01 mol) in anhydrous MeCN (40 ml) was refluxed for approximately 10 h, when TLC monitoring indicated disappearance of benzotriazole; the solvent was then evaporated and the crude mixture was suspended in 200 ml of water. The organic materials were extracted with CH 2 Cl 2 (2 × 150 ml). Both portions were combined, dried over anhydrous Na 2 SO 4 , and then evaporated to give the crude product, further purified by column chromatography on silica gel with EtOAc to afford the title compound (yield: 0.241 g, 78%; colourless solid; Mp. 411-413 K). Single crystal used in X-ray diffraction analysis was obtained at room temperature by slow evaporation of the solution of title compound in the mixture of ethyl acetate and dichloromethane.

Refinement
Hydrogen atoms were placed in geometrically calculated positions (C-H 0.95 Å for aromatic and formyl, 0.99 Å for methylene and 0.98 Å for methyl) and included in the refinement in a riding motion approximation with Uiso(H) = 1.2Ueq(C) [for methyl groups Uiso(H) = 1.5Ueq(C)]. Fig. 1

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating Rfactors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.