摘要 |
Compounds having the formula: <IMAGE> wherein: <IMAGE>R4 = -OCH3, -NH2, NH-R4, R4 being an oligopeptidic residue of which the terminal carboxyl group is blocked as a methyl ester or amide group. They are prepared by reacting the corresponding aminoacids or oligopeptides with an ester or an amide of a second aminoacid or of a second oligopeptide, in presence of an appropriate basic peptidic catalyst. |