Cyclizations protected amines, sodium hydride

The HR of A -protected glutamic acid esters 206 proceeds smoothly under electrochemical conditions to afford carbamates 207. The use of the cosolvent trifluoroethanol prevents formation of the cyclized glutarimide, which is a major byproduct (or only product) with conventional (basic) conditions using bromine and sodium methoxide or by running the electrochemistry in methanol. The several trifluoroethyl carbamates (e.g., 203) that were prepared in these electrochemical HR studies react with primary and secondary amines in the presence of sodium hydride to form unsymmetrical ureas. ... 

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