Ethyl 5,8-dibromo-2-dibromomethyl-6,7-dimethoxyquinoline-3-carboxylate

The title compound, C15H13Br4NO4, was obtained via radical bromination reaction of ethyl 6,7-dimethoxy-2-methylquinoline-3-carboxylate and N-bromosuccinimide (NBS) in the presence of benzoyl peroxide (BPO) under photocatalytic conditions. The quinoline ring system is approximately planar with a maximum deviation from the mean plane of 0.035 (1) Å. The dihedral angle between the six-membered rings is 2.33 (2)°. The methoxy O atoms of the two neighboring methoxy groups are in-plane while their methyl C atoms are located on either side of the quinolyl ring plane at distances of −1.207 (1) and 1.223 (1) Å.

The title compound, C 15 H 13 Br 4 NO 4 , was obtained via radical bromination reaction of ethyl 6,7-dimethoxy-2-methylquinoline-3-carboxylate and N-bromosuccinimide (NBS) in the presence of benzoyl peroxide (BPO) under photocatalytic conditions. The quinoline ring system is approximately planar with a maximum deviation from the mean plane of 0.035 (1) Å . The dihedral angle between the six-membered rings is 2.33 (2) . The methoxy O atoms of the two neighboring methoxy groups are in-plane while their methyl C atoms are located on either side of the quinolyl ring plane at distances of À1.207 (1) and 1.223 (1) Å .
In previous works, we have reported the synthesis of some new quinoline derivatives (Yang et al., 2007(Yang et al., , 2008. Herein, we report the synthesis and structure determination of a new Bromine-containing quinoline derivative, resulting from the radical bromination of ethyl 6,7-dimethoxy-2-methylquinoline-3-carboxylate under photocatalytic conditions. Our attempt to brominate the methyl group linked at C-2 position of quinoline ring, which has an acetal function at C-3, failed and led to 5,8-Dibromo-2-dibromomethyl-6,7-dimethoxy-quinoline-3-carboxylic acid, ethyl ester and other by-pruducts. This compound is the result of a unwanted reaction. The molecular geometry of the title compound is illustrated in Fig 1. The title molecule contains an approximate planar quinolyl moiety with a maximum deviation from the mean plane of 0.035 (1)Å. The dihedral angle between the sixmembered rings is 2.33 (2)°. The methoxy O atoms of the two neighboring methoxy groups are in-plane and their methyl C atoms locate on both sides of the quinolyl ring plane with maximun out-of-plane deviations of -1.207 (1) and 1.223 (1)Å, respectively.

Experimental
The title compoud was syntheized by treating 1mmol of ethyl 6,7-dimethoxy-2-methylquinoline-3-carboxylate with 1.5mmol of N-bromosuccinimide (NBS) in presence of 0.5mmol of Benzoyl Peroxide (BPO) in CCl3 under photocatalytic conditions. The mixture was then cooled and filtered off and the filtrate was concentrated under reduced pressure. The crude product was purified by silica gel column chromatography with the gradient mixture of petroleum ether and ethyl acetate (v : v = 30 : 1) to afford the white product. Crystals suitable for X-ray analysis were obtained by slow evaporation of the mixted solution of petroleum ether and ethyl acetate of the title compound.

Refinement
The H atoms were positioned geometrically and allowed to ride on their parent atoms, with C-H = 0.93-0.98 Å, with U iso (H) = 1.2 U eq (C) or 1.5U eq (C methyl ).

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 > 2sigma(F 2 ) is used only for calculating R-factors(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.