N-[(2-Chloro-8-methylquinolin-3-yl)methyl]-4-methoxyaniline

In the title compound, C18H17ClN2O, the quinoline ring system is essentially planar; the r.m.s. deviation for the non-H atoms is 0.04 Å with a maximum deviation from the mean plane of 0.026 (4) Å for the C atom bonded to the –CH2– group. The methoxy-substituted benzene ring forms a dihedral angle of 70.22 (4)° with this ring system. The crystal structure can be described as zigzag layers in which the quinoline ring systems are parallel to (011) and molecules are connected via intermolecular N—H⋯N hydrogen bonds, forming chains along [100]. The crystal studied was an inversion twin with a 0.86 (5):0.14 (5) domain ratio.

In the title compound, C 18 H 17 ClN 2 O, the quinoline ring system is essentially planar; the r.m.s. deviation for the non-H atoms is 0.04 Å with a maximum deviation from the mean plane of 0.026 (4) Å for the C atom bonded to the -CH 2group. The methoxy-substituted benzene ring forms a dihedral angle of 70.22 (4) with this ring system. The crystal structure can be described as zigzag layers in which the quinoline ring systems are parallel to (011) and molecules are connected via intermolecular N-HÁ Á ÁN hydrogen bonds, forming chains along [100]. The crystal studied was an inversion twin with a 0.86 (5):0.14 (5) domain ratio.

Comment
The importance of quinoline and its derivatives is well recognized by synthetic and biological chemists (Elderfield et al., 1960;Wright et al., 2001;Sahu et al., 2002;Bringmann et al., 2004;Kournetsov et al., 2005). Compounds possessing this ring system such as aminoquinolines, have wide applications as drugs and pharmaceuticals. Many derivatives of aminoquinolines have been reported as plant resistance factors as topical antiseptic (Albert et al. 1955), analgesic (Mouzine et al., 1980) and antimalarials (Lyle et al., 1967). Therefore, considerable efforts have been directed towards the preparation and synthetic manipulation of these molecules. Of the many methods available for the synthesis of amines, the most widely used is the reduction of amides (Cope et al., 1963) and nitro compounds (Ohta et al., 1989) with LiAlH 4 . Reduction of azides (Hatanaka et al., 1981) and nitro compounds (Smith, 1994) with H 2 /Pd have been also reported. Another important and simple method has been disclosed by Borch et al. (1971) which employs NaBH 3 CN at pH≈6 to reduce imines to the corresponding amines. In an ongoing project in our laboratory based on the synthesis of functionalized quinolines (Boulcina et al., 2007;2008), we require an efficient route for the synthesis and transformations of these heterocycles. Herein, we report an efficient and general procedure for the synthesis of a new aminoquinoline derivative derived from 2-chloro-8methyl-3-formylquinolines. The use of NaBH 3 CN as a reducing agent of the corresponding imines was the methodology of choice to accomplish this task. The crystal structure of the title compound (I) is determined herein.
The molecular structure and the atom-numbering scheme of (I) are shown in Fig. 1. The quinoline ring system is essentially planar; the rms deviation for the non-H atoms is 0.04 Å with a maximum deviation from the mean plane of -0.026 (4)Å for the C atom bonded to the -CH 2 -group. The methoxy substituted benzene ring forms a dihedral of 70.22 (4)° with this ring system. The crystal structure can be described as zig-zag layers in which the quinoline ring systems are parallel to the (011) plane and moleclues are connected via intermolecular N-H···N hydrogen bond forming chains along [100]. The crystal is an inversion twin with a 0.86 (5):0.14 (5) ratio of domains.

Experimental
A mixture of 2-chloro-8-methyl-3-formylquinoline (5 mmol) and 4-methoxyaniline (5 mmol) in methanol (10 ml) was stirred at ambient temperature. On completion of the reaction, as indicated by TLC, the mixture was then filtered and the resulting product was washed with cold methanol. The product thus obtained as slightly yellow powder, could be used in the next step without purification. Further recrystallization from methanol yields pure imine. The appropriate imine (1 mmol) and NaBH 3 CN (3 mmol) in methanol (10 ml) were stirred for 24 h, diluted with cold water (20 ml), and left for several hours.
The resulting solid was filtered off, washed with water, then with ethanol and with hexane. N-((2-chloro-8-methylquinolin-3-yl)methyl)-4-methoxybenzenamine was recrystallized from ethanol and identified by IR, 1 H and 13 C NMR spectroscopies. Crystals of the title compound were obtained by slow crystallization from a methanol solution.
supplementary materials sup-2 Refinement All H atoms were vizible in difference Fourier maps but were introduced in calculated positions and treated as riding on their parent C atom (with C-H = 0.93-0.97Å and U iso (H) =1.2 or 1.5(U eq carrier atom)), except for H13N which was located in a difference Fourier map and refined isotropically. Fig. 1. The molecular structure of the title compound with the atomic labelling scheme. Displacement are drawn at the 50% probability level.