PALLADIUM -CATALYZED SONOGASHIRA SYNTHESIS OF MONO-AND BIS• ALKYNYLATED DERIV ATIVES OF QUINOLINE-5,8-DIONE AND THEIR ANTIMICROBIAL ACTIVITY
ABSTRACT The synthesis of five mono- and five bis-alkynylated derivatives of quinoline-5,8-diones is reported. The intermediate 6,7-dibromoquinoline-5,8-dione was obtained by nitrosation of 8- hydroxyquinoline, followed by reduction and subsequent bromination and oxidation. The coupling reaction of 6, 7-dibromoquinoline-5 ,8-dione via palladium-catalyzed Sonogashira cross-coupling gave the alkynylated products. The chemical structures of the products were confirmed using spectroscopic methods which include UV-visible spectrophotometry, Fourier Transform-Infrared (FT-IR) spectroscopy, 'H and 'C-NMR spectroscopy. ...
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