METHOD OF OBTAINING PEPTIDES OR SALTS THEREOF

The invention relates to novel peptides of formula (I), A-Try-B-Asp-Phg-NH 2 (I) wherein A is tert.-butoxycarbonyl-aminooxy-acyl, benzyloxycarbonyl-aminooxy-acyl, (aminooxy)-acyl or E-aminooxy-acyl, wherein E is benzoyl or straight-chained or branched C1-5 aliphatic acyl, and B represents methionyl, leucyl, norleucyl, norvalyl or 2-amino-decanoyl, or acid addition salts or complexes thereof. The novel compounds according to the invention exert gastrin effects and can be applied to advantage in the diagnostics and therapy. The novel compounds of formula (I) are prepared according to the invention by reacting a tetrapeptideamide of formula (II), H-Try-B-Asp-Phg-NH 2 (II) wherein B is as defined above, with an (aminooxy)-acyl containing compound of the general formula A1-X, wherein A1 has the same meanings as A with the exception of the (aminooxy)-acyl, and X is hydroxy group, halogen, pivaloyloxy, a group of the formula R-O-CO2- (wherein R is lower alkyl, phenoxy which can have a nitro substituent or one or more halogen or N-succinimidoxy.