Carbamate esters also arise via alcoholysis of carbamoyl chlorides:
:RNC(O)Cl + ROH → RNCOR + HCl
Alternatively, carbamates can be formed from chloroformates and amines:
:ROC(O)Cl + RNH → RNCOR + HCl
Carbamates may be formed from the Curtius rearrangement, where isocyanates formed are reacted with an alcohol.
:RCON → RNCO + N
:RNCO + R′OH → RNHCOR′