Derivatives of 2,6-diamino-3-haloheptanedioic acid

A 2,6-diamino-3-haloheptanedioic acid derivative having the formula ##STR11## wherein R is hydroxy, (C.sub.1 -C.sub.4)alkoxy or an amino acid, dipeptide or tripeptide residue said amino acid, dipeptide or tripeptide residue being composed of the amino acid selected from the group consisting of glycine and the L-isomers of alanine, methionine, valine, leucine and isoleucine;

• R.sub.1 is hydrogen or an amino acid, dipeptide or tripeptide residue dipeptide or tripeptide residue being composed of the amino acid selected from the group consisting of glycine and the L-isomers of alanine, methionine, valine, leucine and isolencine, and there simple amides, with the proviso that when R.sub.1 is an amino acid, dipeptide or tripeptide residue, then R must be hydroxy, and with the further proviso that when R is an amino acid, dipeptide or tripeptide residue, then R.sub.1 must be hydrogen;
• X and Y are independently hydrogen, fluorine or chlorine, with the proviso that X and Y cannot both be hydrogen;
• and the pharmaceutically acceptable salts or optical isomers thereof.