Conformational variability in sulfonamide chalcone hybrids : crystal structure and cytotoxicity

Abstract

Four sulfonamide-chalcone derivatives were prepared and their crystal structure were elucidated by single-crystal X-ray diffraction technique. They were synthesized by Claisen-Schmidt condensation reaction between N -(4-acetylphenyl)benzenesulfonamide or N -(4-acetylphenyl)- 2,5-dichlorobenzenesulfonamide with benzaldehyde or p -nitrobenzaldehyde. Values of Z’ > 1 are found in three compounds as a consequence of conformerism. The chalcone molecular backbones are featured by different levels of planarity in their conformers. Another conformational variability is in its benzenesulfonamide moiety. In the compound came from N -(4-acetylphenyl) benzenesulfonamide and benzaldehyde, there is a rotation of ca. 180° on the bond axis bridging the sulfonamide and chalcone motifs of one conformer if the two others are taken as references. The cytotoxic activity of all compounds synthesized here and of two other related sulfonamide chalcones was also assessed against three cancer cell lines (SF-295, HCT-8 and MDA-MB-435). The para -nitro compounds were the most active ones among all those tested, regardless of substitution pattern in benzenesulfonamide core.