A large-scale synthesis of [MeTyr1, MeArg7, D-Leu8]dynorphin A-(1-8)-NHEt (E-2078) by application of the trifluoroacetic acid-pentamethylbenzene deprotecting procedure in the final stage.

A large-scale synthesis of [MeTyr1, MeArg7, D-Leu8]dynorphin A-(1-8)-NHEt (E-2078), which is a systemically active dynorphin A-(1-8) analogue, was accomplished by the classical solution method applying the trifluoroacetic acid-pentamethylbenzene deprotecting procedure in the final stage.