[Synthesis of [Trp(1-But)9]- and [Trp(2,5,7-But3)9] corticotropin-(1--19)-nonadecapeptideamide (author's transl)].

The title analogues of corticoptropin-(1--19)-nonadecapeptidamide in which the tryptophan residue in position 9 has been replaced by tert-butylated tryptophan derivatives, were prepared according to the methods of conventional peptide synthesis in solution. Both analogues showed remarkable steroidogenic activity as measured by Sayers test. The unexpectedly high biological potency is discussed.