Peptide, process for preparation thereof and use thereof

摘要

The invention deals with novel peptides useful for the therapeutic treatment of infectious diseases caused by pathogenic microorganisms, having the structure <IMAGE> wherein R1 is substituted or unsubstituted lower alkanoyl, or substituted or unsubstituted aralkanoyl, R2 and R3 are each carboxy or protected carboxy, R4 is hydrogen or an amino protective group, and R5 is hydrogen or lower alkyl, and their pharmaceutically acceptable salts.