Scheme 2. Glycoconjugation of a series of alkynylated DPP derivatives via copper-promoted azide–alkyne 1,3-dipolar cycloaddition (CuAAC).a aReactions were carried out at 50 °C for 48 h under N2 in DMF with 10 mol% of CuI and 100 eq. of DIPEA. bReaction carried out with 10 mol% of CuSO4·5H2O and 50 mol% of ascorbic acid. cAverage of 2 trials.
