Polypeptides. Part VII. Variations of the phenylalanyl position in the C-terminal tetrapeptide amide sequence of the gastrins

Abstract

The synthesis is described of analogues of L-tryptophyl-L-methionyl-L-aspartyl-L-phenylalanine amide (the C-terminal sequence of the gastrins) or its N-benzyloxycarbonyl, -t-butoxycarbonyl, or -carbamoyl derivatives wherein the phenylalanyl residue has undergone replacement by other naturally occuring amino-acyl residues or by αα-disubstituted amino-acyl residues, or has been modified by (a) substitution of the aromatic ring in the p-position, (b) hydrogenation of the aromatic ring, (c) switch of the imino-radical from the α- to the β-carbon atom, (d) switch of the phenyl ring from the β- to the α-carbon atom, (e) substitution of an hydroxy-group on the β-carbon atom, or (f) methylation of the imino-group.