Synthesis of two new corticotrophic peptides containing homoarginine in position 8

The octadecapeptide amide I and the tetracosapeptide II containing homoarginine in position 8 have been synthesized according to a generally approved scheme. As a new feature, the hydroxyl functions of the serine and tyrosine residues were protected in the synthesis of the N‐terminal decapeptide. The latter, presumably by its higher solubility in organic solvents, afforded the protected end products in an improved yield. For complete deprotection, however, acid‐treatment of these compounds had to be extended over longer periods than in the absence of the ether functions.