Synthesis and photophysical, thermal and antimycobacterial properties of novel 6-amino-2-alkyl(aryl/heteroaryl)-4-(trifluoromethyl) quinolines

Abstract

The synthesis and structural elucidation of a new series of six 6-amino-2-alkyl(aryl/heteroaryl)-4-(trifluoromethyl) quinolines are reported, yielding 22 to 87% isolated products. This was achieved through a regioselective intramolecular cyclization reaction of novel (Z)-4-((4-aminophenyl)amino)-1,1,1-trifluoro-but-3-en-2-ones in an acidic solvent-free medium, in which alkyl/aryl/heteroaryl = methyl, phenyl, 4-MeC₆H₄, 4-FC₆H₄, 4-NO₂C₆H₄, and 2-furyl. The novel compounds were fully characterized by ¹H-, ¹³C- and ¹⁹F-NMR spectroscopy, GC-MS and single-crystal X-ray diffraction. In addition, the preliminary investigation of photophysical properties of the 6-aminoquinolines (UV-Vis, fluorescence, quantum yield calculations, Stokes shifts, and TD-DFT analysis) and inhibitory activity against M. tuberculosis H37Rv strain was also presented. Thermal analyses were carried out to assess their properties as new materials.