Polypeptides. Part IX. Variations of the methionyl 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 and its N-benzyloxycarbonyl or N-t-butoxycarbonyl derivatives wherein the methionyl residue has undergone replacement by α-aminobutyryl, alanyl, asparaginyl, S-benzylhomocysteinyl, ethionyl, S-ethylcysteinyl, homoseryl, leucyl, S-methylcysteinyl, N-methylnorleucyl, norleucyl, norvalyl, or phenylalanyl residues, or has been converted to the sulphoxide or sulphone.