Amino acids and peptides. Part 42. Application of the 2-adamantyloxycarbonyl (2-Adoc) group to the protection of the imidazole function of histidine in peptide synthesis

Abstract

The N^im-2-adamantyloxycarbonyl (2-Adoc) group has been found to be both suitable for protection of the imidazole function of the histidine residue in peptide synthesis in terms of its stability to trifluoroacetic acid (TFA), tertiary amines and 1-hydroxybenzotriazole (HOBt), and in its reduction of the racemization rate during the coupling reaction. N^im-2-Adoc protection has also been applied successfully to the solid-phase synthesis of thyrotropin-releasing hormone which depends on tert-butoxycarbonyl (Boc)-chemistry.