Synthesis of tryptophan N-glucoside

The naturally occurring l-tryptophan N-glucoside was synthesized using 2-O-pivaloylated glucosyl trichloroacetimidate, which gave β-NIn-glucosides. From 2-O-acetylated donors only tryptophan-1-yl-ethylidene compounds (amide acetals) were obtained. The employment of α-azido l-tryptophan benzyl ester facilitated purification and deprotection and improved the yields of the glycosylation step.