A Reusable FeCl3∙6H2O/Cationic 2,2′-Bipyridyl Catalytic System for Reduction of Nitroarenes in Water

The association of a commercially-available iron (III) chloride hexahydrate (FeCl3∙6H2O) with cationic 2,2′-bipyridyl in water was proven to be an operationally simple and reusable catalytic system for the highly-selective reduction nitroarenes anilines. This procedure conducted under air using 1–2 mol% catalyst presence 4 equiv hydrazine monohydrate (H2NNH2∙H2O) neat at 100 °C 12 h, provided high excellent yields aniline derivatives. After separation aqueous from organic product, residual solution could applied subsequent reuse, without any retreatment or regeneration, several runs only slight decrease activity, proving this process eco-friendly.