Synthesis, crystal structure and biological activity of 2-[2-(quinolin-2-yl)vinyl]-8-hydroxyquinoline and 2-[2-(quinolin-4-yl)vinyl]-8-hydroxyquinoline

Two new isomeric 8-hydroxyquinoline derivatives with quinoline groups have been synthesized by Perkin condensation. Their structures were characterized by EI-MS, H-1 NMR spectroscopy, elemental analysis and FT-IR spectroscopy; crystal structures were determined by X-ray crystallography. 2-[2-(Quinolin-2-yl) vinyl]-8-hydroxyquinoline crystallizes in the tetragonal space group I4(1)/a and 2-[2-(quinolin-4-yl)vinyl]-8-hydroxyquinoline crystallizes in the monoclinic space group P2(1)/n. Hydrogen bonds and intermolecular interactions are observed in the compounds and stabilize their structures. The biological activities were investigated by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay and flow cytometry analysis, and the results revealed that the two compounds had effects on the proliferation of rat mesenchymal stem cells.