Synthesis of asparagine-linked bacillosamine

Various types of protein glycosylation have been identified from prokaryotes. Recent investigations have revealed the presence of N-linked glycoproteins in the pathogenic bacterium, Campylobacter jejuni. The structure of this glycan is unique, consisting of 5 GalNAc and 1 Glc, in addition to 2,4-diacetamido-2,4,6-trideoxy-d-glucopyranose (bacillosamine; Bac), which is N-glycosidically linked to the side chain of asparagine (Asn). We synthesized Bac from a 2-azido-2-deoxy-d-galactose derivative, which was further converted to the Asn-linked form.