Synthesis of Quinoline-2-thiones by Selective Deoxygenative C–H/C–S Functionalization of Quinoline N‑Oxides with Thiourea

Quinoline-2-thiones valuable for synthetic and medicinal chemistry applications were obtained with excellent regioselectivity employing a deoxygenative C–H functionalization of readily available quinoline-N-oxides with thiourea upon activation with triflic anhydride. Unlike the current methods, this approach provides general access to diverse quinoline-2-thiones functionalized with groups of different electronic natures. Experimental simplicity and good to high yields are advantages of this protocol. Given the high reactivity of quinoline-2-thiones, this method provides an entry point for the synthesis of diverse organosulfur quinoline scaffolds.