Scheme 3. Synthesis of Biphenyl Glycosides Evaluating Effect of N-Substitution of GalNAc Ringa.
aReagents and conditions: (a) ACN, 80 °C, 2 h; (b) DCM, (CF3CO)2O/TEA, rt, 1 h; (c) DCM, MsCl/TEA, rt, 3 h; (d) Pd(PPh3)4, Cs2CO3, 1,4- dioxane/water (5:1), 80 °C, 1 h; (e) 33% methylamine in absolute ethanol, rt, 1 h.