Abstract: The invention relates to novel peptides of formula (I),A-Try-B-Asp-Phg-NH.sub. 2 (I)whereinA is tert.-butoxycarbonyl-aminooxy-acyl, benzyloxycarbonyl-aminooxy-acyl, (aminooxy)-acyl or E-aminooxy-acyl, wherein E is benzoyl or straight-chained or branched C.sub.1-5 aliphatic acyl, andB 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.sub. 2 (II)wherein B is as defined above, with an (aminooxy)-acyl containing compound of the general formula A.sub.1 -X, whereinA.sub.1 has the same meanings as A with the exception of the (aminooxy)-acyl, andX is hydroxy group, halogen, pivaloyloxy, a group of the formula R--O--CO.sub.

Abstract: Peptides of the formula:A--Trp--B--Asp--Phe--NH--Ywherein A is tert.-butoxycarbonyl-aminooxy-acyl, benzyloxycarbonyl-aminooxy-acyl, (aminooxy)-acyl, or E-aminooxy-acyl, wherein E is benzoyl or straight-chain or branched C.sub.1-5 aliphatic acyl, B is methionyl, leucyl, norleucyl, norvalyl or 2-amino-decanoyl, and Y is hydrogen or carboxymethoxy, and pharmaceutically acceptable acid-addition salts or complexes thereof have gastric-acid secretion increasing effects.

Abstract: A process for the preparation of L-aspartyl-(O-sulfato-L-tyrosyl)-L-methionyl-glycyl-L-tryptophyl-L-methion yl-L-aspartyl-L-phenylalanine amide, which comprises treating the protected octapeptide amide of the general formula (II) ##STR1## wherein X is BOC, Cbz or Ddz,Y is O.sup.t Bu, OBzl or OH andW is O.sup.t Bu, OBzl or OH,in the presence of an ether with an excess of the complex compound of sulfur trioxide and a tertiary amine containing at least one alkyl group, converting the obtained sulfate ester of the protected octapeptide amide into an alkali metal salt and simultaneously removing the formyl group from the tryptophan unit by reacting the sulfate ester with an alkali metal hydroxide, and then splitting off the remaining protective groups by acidolysis.