Novel Schiff Bases Based on the Quinolinone Skeleton: Syntheses X-ray Structures and Fluorescent Properties

摘要

A series of a new type of Schiff bases >1–>7, derived from 2-phenyl-3-amino-4(1H)-quinolinone and R-salicyladehyde derivatives wherein R = 3-hydroxy (>1), 3,4-dihydroxy (>2), 3-methoxy (>3), 3-carboxy (>4), 3-allyl (>5), 5-chloro (>6), and 5-nitro (>7), was synthesized and structurally characterized. Each of the molecules >1, >3 and >7 consists of three planar moieties (i.e., a quinolinone and two phenyl rings), which are mutually oriented differently depending on the appropriate substituent R and the extent of non-covalent contacts stabilizing the crystal structures. The compounds were studied for their fluorescence properties, where compound >6 yielded the strongest intensity both in the solid phase and in 100 μM ethanol solution with a quantum yield of φ = 3.6% as compared to quinine sulfate used as a standard. The in vitro cytotoxicity of these compounds was tested against the human osteosarcoma (HOS) and breast adenocarcinoma (MCF7) cell lines, revealing no activity up to the concentration of 50 µM.