Peptide derivatives of .beta.-chloro-L(Z)-dehydro-glutamic acid

A compound represented by the general formula (I) ##STR6## wherein X is a hydrogen atom or an amino acid or oligopeptide residue obtained by removing, from an amino acid or oligopeptide, the hydroxyl group of the terminal carboxyl group;

• Y and Z are each a hydroxyl group which may optionally be protected, or an amino acid or oligopeptide residue obtained by removing, from an amino acid or oligopeptide, the hydrogen atom of the terminal amino group;
• when Y and Z are each said amino acid or oligopeptide residue, each terminal carboxyl group of the respective residues may be protected by a same or different protecting group;
• and a case is excluded where X is a hydrogen atom and Y and Z are each a hydroxyl group which may be protected.