Iodine-mediated glycosylation en route to mucin-related glyco-aminoacids and glycopeptides.
The use of iodine-DDQ as a promoter for glycosylation of Fmoc-Ser-OBn and Fmoc-Thr-OBn with phenylseleno 3,4,6-tri-O-acetyl-2-azido-2-deoxy-alpha-D-galactopyranoside in toluene-dioxane gave 49% and 73% yields, respectively, of the corresponding alpha-glycosides as the sole glycoside products. Reductive acetylation of the azide groups and cleavage of the benzyl esters by hydrogenolysis gave building blocks that were used in solid-phase synthesis to prepare triglycosylated tetrapeptides (Ac(3)GalNAc-alpha-Ser)(3)-Gly and (Ac(3)GalNAc-alpha-Thr)(3)-Gly in 27% and 49% overall yield, respectively.
Kärkkäinen
Tiina S
TS
School of Chemical Sciences and Pharmacy, University of East Anglia, Norwich, UK.
Ravindranathan Kartha
K P
KP
Macmillan
Derek
D
Field
Robert A
RA
D000116:Acetylgalactosamine / Q000031:analogs & derivatives; D000596:Amino Acids / Q000737:chemistry*; D006020:Glycopeptides / Q000138:chemical synthesis*; D006031:Glycosylation; D007455:Iodine / Q000737:chemistry*; D009077:Mucins / Q000737:chemistry; D012694:Serine / Q000031:analogs & derivatives / Q000737:chemistry; D013912:Threonine / Q000031:analogs & derivatives / Q000737:chemistry
D000596:Amino Acids; D006020:Glycopeptides; D009077:Mucins; D013912:Threonine; D012694:Serine; D007455:Iodine; D000116:Acetylgalactosamine