Selective Solid Phase Synthesis of Ureas and Hydantoins from Common Phenyl Carbamate Intermediates

An efficient method for selective, solid phase synthesis of unsymmetrical ureas and hydantoins from a common phenyl carbamate dipeptide intermediate is decribed. Reaction of phenyl carbamate 6 with primary or secondary amines (R 3 R 4 NH) in THF results in selective formation of ureas 8, whereas its treatment with a tertiary amine base (iPr 2 NEt or DBU) in DMF affords clean conversion to hydantoins 10 .