Synthesis of carbamates by reaction of amines with dialkyl carbonates: influ-ence of leaving and entering groups

A number of carbamates were synthesised thorough a halogen free process by reacting amines with symmetrical and unsymmetrical carbonates. The results obtained showed a specific trend of preferred leaving group (in the dialkyl carbonates) depending if a catalyst or a base was used. On the other hand, investigations conducted on the preferred entering groups (amines) for the synthesis of carbamates showed the same trend if a catalyst or with a base was used. Finally, in accordance with the results ob-tained, it was possible to synthesise sterically hindered carbamates in high yield by transeterification of methyl carbamate with a sterically hindered alcohol