Chemical Synthesis of N-Acetylmuramyl Peptides with Partial Structures of Bacterial Cell Wall and Their Analogs in Relation to Immunoadjuvant Activities

N-Acetylmuramyl peptides of successive length corresponding to the partial structures of cell wall in Staphylococcus aureus were synthesized in order to elucidate the minimum effective structure responsible for immunoadjuvant activity of bacterial cell walls. In view of the finding that N-acetylmuramyl-l-alanyl-d-isoglutamine was the least structure moiety for exhibition of the activity, nine analogs of either N-acetylmuramyl amino acid or N-acetylmuramyl dipeptide were also synthesized.