Synthesis of carbamates from amines and N-tosylhydrazones under atmospheric pressure of carbon dioxide without an external base

The methodology for the synthesis of carbamates via the base-promoted coupling of carbon dioxide, amines, and N-tosylhydrazones using potassium carbonate as the base and the pressure of 4 MPa of carbon dioxide has been published by Jiang et al. (2015). We demonstrated that this method provides the desired carbamates under just 1 atm of carbon dioxide without the addition of a base promoter. Thus, carbamates were successfully synthesized under mild reaction conditions in moderate to high yields.