Methods for the synthesis of various novel substituted dipeptide derived nitrogen-containing heterocyclic compounds (I) and their pharmaceutically acceptable salt derivatives are provided. The compounds of the invention are claimed and are useful as medicaments for the treatment or prevention of disease in a mammal, for example a human. In particular the compounds are useful as immuno therapeutics and anti -microbial drugs or vaccines. These heterocyclic derivatives can be used as an active agent in a pharmaceutical, as well as a diagnostic utility.
