Facile synthesis of N-Fmoc-serine-S-GlcNAc: a potential molecular probe for the functional study of O-GlcNAc

A methabolically stable β-N-acetylglucosaminyl-1-thio-N-Fmoc-serine (S-GlcNAc-Ser) derivative was synthesized in two procedures: one involving a coupling of a readily obtainable 1-pseudo-thiourea of GlcNAc (S-GlcNAc) and iodo-N-Boc- -alanine benzyl ester, and the other utilizing a modified Mitsunobu reaction of GlcNAc-SH and a serine derivative.