| dc.description.abstract | The present work describes the synthesis, structural study and evaluation of the
photophysical properties of novel 6-amino-4-(trifluoromethyl)quinolines, as well as their
application in obtaining an unpublished series of 2-alkyl(aryl/heteroaryl)-6-(4-alkyl(aryl)-1H-
1,2,3-triazol-1-yl)-4-(trifluoromethyl)quinolines, 2-alkyl = Me; 2-aryl(heteroaryl) = Ph, 4-Me-
C6H4, 4-F-C6H4, 4-NO2-C6H4, 2-furyl; 4-alkyl(aryl) = -CH2OH, -(CH2)5CH3, Ph. Structural and
electronic properties were investigated by mass spectrometry (GC/MS), 1H-, 13C- and 19F-NMR
and by single-crystal X-ray diffraction.
The methodology begins with the synthesis of an unprecedented series of precursors
namely (Z)-4-alkyl(aryl)-4-(4-aminophenyl)amino)-1,1,1-trifluoro-3-alken-2-ones (3),
obtained from reactions between 4-methoxy-1,1,1-trifluoro-3-alken-2-ones (1) and pphenylenediamine
(2) in yields of 71-87%. The enaminoketones 3, on the other hand, were
successfully used in regioselective reactions of intramolecular cyclization in sulfuric acid,
bringing the corresponding 6-amino-4-(trifluoromethyl)quinolines (4) in yields of 22-87%.
In sequence, the 6-aminoquinoline derivatives 4 had their photophysical properties as
absorption, emission, fluorescence quantum yield and Stokes displacement evaluated and
related to theoretical calculations (TD-DFT). An initial evaluation of thermal stability using
DSC/TGA techniques was also obtained in the present study. The quinolines 4 were also
converted to an unpublished series of 6-azido-4-(trifluoromethyl)quinolines (5) in 78-87%
yields employing diazonium salts and sodium azide.
Finally, the azides originating 5 reacted with different terminal alkynes (6-8) under a
copper-catalysed 1,3-dipolar cycloaddition reactions (CuAAC - Click Chemistry), to performed
the exclusive synthesis of 1,4-disubstituted 1,2,3-triazolylquinoline derivatives (9-11) in yields
of 77-95% (12 examples). | |
