Preparation of N-Acetylmuramyl- l -[U-14C]alanyl- d -isoglutamine via a Novel Synthetic Route

For the investigation on the action mechanism of immunoadjuvant active N-acetylmuramyl-l-alanyl-d-isoglutamine, its labeled compound, i.e., N-acetylmuramyl-l-[U-14C]alanyl-d-isoglutamine was synthesized. For this purpose, an entirely novel synthetic route for the muramyl dipeptide was exploited using cold materials and applied to the preparation of the labeled compound. A convenient synthetic procedure of isoglutamine derivatives is also described.