(E)-5-Bromo-3-(2,6-dichlorobenzylidene)indolin-2-one

The title compound, C15H8BrCl2NO, crystallizes with two independent molecules in the asymmetric unit. The dihedral angles between the two aromatic rings are 62.74 (9) and 63.50 (6)° in the two independent molecules. In the crystal, the molecules are connected by N—H⋯O hydrogen bonds, forming two centrosymmetric dimers.

The title compound, C 15 H 8 BrCl 2 NO, crystallizes with two independent molecules in the asymmetric unit. The dihedral angles between the two aromatic rings are 62.74 (9) and 63.50 (6) in the two independent molecules. In the crystal, the molecules are connected by N-HÁ Á ÁO hydrogen bonds, forming two centrosymmetric dimers.
(E)-5-Bromo-3-(2,6-dichlorobenzylidene)indolin-2-one H. Zhang, H. Ankati, S. K. Akubathini and E. Biehl Comment 3-Substituted indoline-2-ones have well recognized pharmacological properties, including antitumor properties (Andreani et al., 2006), as well as the function as receptor tyrosine kinase (RTK) inhibitors (Sun et al., 2003) and neuroprotective properties (Johnson et al., 2005). For studying the biological properties a series of 3-substituted indoline-2-one derivatives have been synthesized in our lab and their neuroprotective activities have been tested (Ankati et al., 2009, Balderamos et al. 2008. As a part of our research on the relationship between the biological activities and solid structures a couple of crystal structures of the derivatives have been carried out (Zhang et al., 2008(Zhang et al., , 2009a(Zhang et al., , 2009b. The crystal structure confirmed the E configuration of the compound. The title compound consists of an oxindolyl and a dichlorophenyl unit (Fig 1). The dihedral angles between the two aromatic rings are 62.74 (9) and 63.50 (6)°, respectively, for the two independent molecules. The crystal structure revealed that the intermolecular H-bonds (Table 1), linking the two inverted molecules, form an octa cyclic membered ring and a dimer (Fig 2) is constructed.
Experimental 2,6-Dichlorobenzaldehyde (1 mmol) was added to a mixture of 5-bromo-2-oxindole (1 mmol) and piperidene (0.1 mmol) in ethanol (4 ml) were placed in a microwave test tube. The tube was then capped and charged into a CEM microwave instrument. The mixture was irradiated with 250 psi pressure and at a temperature of 140°C for 10 minutes. Then the reaction mixture was left overnight at room temperature. The obtained solid was collected by filtration and washed with cold ethanol.
The crude product was purified by recrystallization from ethanol and the yellow colored single-crystal sample was obtained.

Refinement
All H atoms were placed in calculated positions and included in the final cycles of refinement using a riding model, with distances N-H = 0.86 Å and C-H = 0.93 Å, and displacement parameters U iso (H) = 1.2U eq (N,C).