Synthesis of Thyrotropin-Releasing Hormone-Related Peptides Using Nα-tert-Bytyloxycarbonyl-ω-(N-tert-butyloxycarbonylcarbamoyl)-α-amino Acids

Application of Nα, Nca-di-tert-butyloxycarbonylhomoglutamine to synthesis of thyrotropin-releasing hormone (TRH) analogs was examined. The δ-lactam formation from homoglutaminylpeptides took place more easily than γ-lactam formation from glutaminylpeptides in water or dioxane containing acetic acid. [pHgu1, Nva2]-TRH had dose-dependent antagonistic activity against pentobarbital anesthesia in mice, but almost no binding activity to TRH receptor in rat brain.