From Surprising Solvothermal Reaction to Uncommon Zinc(II)-Catalyzed Aromatic C-H Activation Reaction for Direct Nitroquinoline Synthesis.

In this work, we first found a surprising solvothermal reaction for direct dinitration of quinoline derivative. To explore the application in direct nitroquinoline synthesis, this reaction was subsequently modified as an equivalent reaction in a Schlenk tube. More significantly, after a constant attempt, nitrated derivative was obtained in optimized condition with a zinc(II) sulfate catalyst, where some substrates with strong electron-withdrawing group were first nitrated by a directly catalyzed condition. This new zinc(II)-catalyzed aromatic C-H activation reaction is the first example of direct dinitration by a single catalyst, which will be a new facile and environmentally friendly strategy to access synthetically useful nitroquinoline derivative.