N-(9-Fluorenylmethoxycarbonyl)-O-(3,4,6-tri-O-acetyl-2-azido-2-desoxy-α-D-galactopyranosyl)-L-serin-tert-butylester synthesis

Yield:110797-36-9 89%

Reaction Conditions:

with trimethylsilyl trifluoromethanesulfonate

Steps:

4.4 Synthesis of per-O-acetylated GalNAc α-linked to Fmoc-protected serine as a building block for solid phase glycopeptide synthesis of Tn-MUC1

Synthesis of the Tn building block, per-OAc-GalNAcα(Fmoc)Ser, was carried out similar to that reported.³⁶ Briefly, glycosylation of 2-azido-2-deoxygalactosyl trichloroacetimidate donor (400mg, 844μmol) with Fmoc (at amino group) and t-butyl (at the carboxyl group) protected serine (290mg, 760μmol) using TMSOTf (20μL, 84μmol) as a promoter provided glycosylated product with a good yield (469mg, 89%). Subsequent conversion of the azido group to an N-acetyl group using Zn/THF/HOAc/Ac₂O (472mg, 80%) and removal of the t-butyl group using TFA/H₂O produced the glycosylated Fmoc-protected amino acid building block per-OAc-GalNAcα(Fmoc)Ser in quantitative yield (442mg, 100%).

References:

Malekan, Hamed;Fung, Gabriel;Thon, Vireak;Khedri, Zahra;Yu, Hai;Qu, Jingyao;Li, Yanhong;Ding, Li;Lam, Kit S.;Chen, Xi [Bioorganic and Medicinal Chemistry,2013,vol. 21,# 16,p. 4778 - 4785]