(3RS,4SR)-Methyl 4-(2-chloro-5,8-dimethoxyquinolin-3-yl)-1-phenylpyrrolidine-3-carboxylate

The molecule of the title compound, C23H23ClN2O4, contains a quinolyl unit linked to a functionalized pyrrolidine system with a 3,4-trans arrangement of the substituents. The unit cell contains two stereoisomers that have the absolute stereochemistry 3S,4R and 3R,4S. The pyrrolidine ring adopts a twist conformation with pseudo-rotation parameters P = 258.2 (3)° and τ(M) = 35.3 (1)°. The packing is stabilized by C—H⋯π interactions and offset π–π stacking (centroid-to-centroid distance = 3.849 Å, interplanar distance = 3.293 Å and slippage = 1.994 Å) between phenyl rings, leading to a two-dimensional network.


Crystal data
Cg1 is the centroid of the C17-C22 ring.

Comment
Quinolines derivatives have attracted considerable interest for many years due to their presence in the skeleton of a large number of bioactive compounds and natural products (Padwa et al., 1999;Sahu et al. 2002). For example, quinoline alkaloids, such as quinine, chloroquin, mefloquine and amodiaquine, are used as efficient drugs for the treatment of malaria (Robert & Meunier, 1998;Dow et al., 2006). On the other hand, pyrrolidine containing compounds are also of significant importance because of their biological activities and widespread employment in catalysis (Witherup et al., 1995;Kravchenko et al., 2005). As a part of our program related to the preparation and biological evaluation of quinolyl derivatives (Belfaitah et al., 2006;Bouraiou et al., 2008Bouraiou et al., , 2007aRezig et al., 2000;Moussaoui et al., 2002), we have previously reported the preparation of some 3-pyrrolylquinoline derivatives via an 1,3-dipolar cycloaddition/oxydation key sequence from quinolinyl α,β-unsaturated esters as starting materials (Menasra et al., 2005). In a continuation of our efforts in this area, we report here the crystal structure of new N-phenylpyrrolidine derivative bearing a quinoline ring at C-3 and ester group at C-4 via an 1,3-dipolar cycloaddition reaction.
The asymmetric unit of title compound contains a quinolyl unit linked to a functionalized pyrrolidine system with a 3,4trans arrangement of the substituents (Fig. 1). The two rings of quinolyl moiety are fused in an axial fashion and form a dihedral angle of 0.67 (6)° and this quasi plane system forms dihedral angles of 83.76 (7)° with the phenyl ring.The pyrrolidine was obtained with conservation of the stereochemistry of starting alkene, giving only one diastereoisomer with no evidence of any other isomers in the 1 H NMR spectra or thin-layer chromatography of the crude product. X-ray crystallography of (I) showed an asymmetric unit which contains only one stereoisomer and the analysis of the unit cell demonstrate that the second stereoisomer is generated via a symmetry element. The two stereoisomers have for each one, the absolute stereochemistry 3S,4R and 3R,4S of the new stereocenters created in the cycloaddition reactions.
The packing is stabilized by C-H···π interaction involving the C17-C22 phenyl ring (Table 1). Offset π···π stacking between this phenyl ring and the symmetry (-x, -y, -z) related ring might also be considered with a centroid-to-centroid distance of 3.849 Å, an interplanar distance of 3.293Å and a slippage of 1.994Å (Spek, 2003). These weak interactions build up a two dimensional network (Fig. 2).

Experimental
The title compound I was synthesized by refluxing 1.0 mmol of (E)-methyl 3-(2-chloro-5,8-dimethoxyquinolin-3-yl) acrylate, 2.0 mmol of N-phenylglycine, and 5.0 mmol of CH 2 O in dry toluene (5.10 -3 M). The contents were then cooled and filtered off and the filtrate was concentrated under reduced pressure. The residue was subjected to column chromatography sup-2 (silica gel, eluent: CH 2 Cl 2 ) to afford pure product. Crystals suitable for X-ray analysis were obtained by slow evaporation of a dichloromethane solution of (I).

Refinement
All H atoms were localized on Fourier maps but introduced in calculated positions and treated as riding on their parent C atom.