Ruthenium-Na2CO3-catalyzed one-pot synthesis of ring-hydrogenated carbamates from aromatic amines and organic carbonates under H-2

Abstract

A facile and efficient one-pot procedure for the synthesis of ring hydrogenated carbamates from aromatic amine and alkylene carbonate under H-2 gas pressure has been developed using a heterogeneous catalyst system comprising ruthenium and alkali metal carbonates. The effects of temperature, H-2 pressure, catalyst (types of loaded metal and their supports), molar ratio of substrate/catalyst, and solvent were also investigated. Among the alkali metal carbonates, the sodium carbonate was found as best promoter for nucleophilic attack and ring-opening (NARO) reaction and thus increased the yield of ring hydrogenated carbamate up to 88% when using Ru/C as ring hydrogenation (RH) catalyst. This catalyst system could be reused at least five times without significant loss of activity, which makes this process cost-effective and eco-friendly.