Ethyl 3-(2-chloro-5,8-dimethoxyquinolin-3-yl)-2-cyanooxirane-2-carboxylate

The title molecule, C17H15ClN2O5, contains a quinolyl unit linked to a functionalized oxirane system with a 2,3-trans arrangement of the substituents (ester group versus quinolyl). The structure can be described as being built up from zigzag layers parallel to (10). The heterocyclic ring of the quinolyl unit forms a dihedral angle of 60.05 (1)° with the oxirane plane. The crystal packing is stabilized by intermolecular C—H⋯O and C—H⋯N hydrogen bonding, resulting in the formation of an infinite three-dimensional network and reinforcing the cohesion between the layers.

The title molecule, C 17 H 15 ClN 2 O 5 , contains a quinolyl unit linked to a functionalized oxirane system with a 2,3-trans arrangement of the substituents (ester group versus quinolyl). The structure can be described as being built up from zigzag layers parallel to (110). The heterocyclic ring of the quinolyl unit forms a dihedral angle of 60.05 (1) with the oxirane plane. The crystal packing is stabilized by intermolecular C-HÁ Á ÁO and C-HÁ Á ÁN hydrogen bonding, resulting in the formation of an infinite three-dimensional network and reinforcing the cohesion between the layers.
Oxiranes are important intermediates and starting materials which have found much use in synthetic organic chemistry owing to their ease of formation and ready activity toward nucleophiles (Hanson et al., 1991;Kumar et al., 2007;Das et al. 2007). In addition, natural occurring oxiranes are associated with various biological activities (Cross, 1960;Bino, 1980;Pearson et al., 1981;Marco-Contelles et al., 2004). 2-cyano-2-alkoxycarbonyloxiranes proved to be versatile reagents from which a large variety of compounds might be synthesized (Boukhris et al., 1996;Ammadi et al., 1999). In connection with our research program aimed at the synthesis and the biological evaluation of quinoline derivatives Benzerka et al., 2008;Ladraa et al., 2010), we report in this paper the synthesis and the structure determination by X-ray of a new quinoline compound where quinolyl moiety is linked to functionalized oxirane system. The reactivity of this compound and its analogues toward nucleophiles is under investigation.
The molecular geometry and the atom-numbering scheme of (I) are shown in Fig. 1.
In the asymmetric unit of title compound the oxiranes unit bearing an ester and cyano groups at C3 and quinolyl moiety at C2.
The two rings of quinolyl moiety are fused in an axial fashion and form a dihedral angle of 2.43 (5)°. The heterocycle ring of quinolyl unit form also with oxirane plane a dihedral angle of 60.05 (1)°.
The crystal packing can be described as layers in zig zag parallel to (1-10) plane (Fig. 2). A weak hydrogen bond interactions (C-H···N=3.434 (3) Å)along the [110] directions ensure the stability in the same layer. (as reported by Desiraju & Steiner, 1999) These layers are linked together by a classical weak C-H···O interactions and π-π stacking The crystal packing is stabilized by intra and intermolecular hydrogen bond (C-H···N and C-H···O) and π-π stacking, resulting in the formation of infinite three-dimensional network linked these layers toghter and reinforcing a cohesion of structure (Fig. 3).
Hydrogen-bonding parameters are listed in table 1.

Experimental
The title compound was obtained by oxidation of (E)-ethyl-3-(2-chloro-5,8-dimethoxyquinolin-3-yl)-2-cyanoacrylate with 2,5 equivalents of m-chloroperoxybenzoic acid in dichloromethane at room temperature in the presence of 1,2 equivalents of potassium carbonate. Column chromatography (silica gel, eluant: CH 2 Cl 2 ) of the residue afforded pure product as yellow solid. Crystals suitable for X-ray analysis were obtained by slow evaporation of a dichloromethane / methanol solution.