Microwave-enhanced ionothermal CuAAC for the synthesis of glycoclusters on a calix[4]arene platform

摘要

A tetra-azido calix[4]arene derivative was allowed to react with ethynyl tetra-O-benzyl-C-galactoside in the presence of CuI and i-Pr2EtN in three different ionic liquids, that is, [C(8)dabco][N(CN)(2)], [C(8)dabco][Br], and Ammoeng 110. Reactions were performed at 80 degrees C by thermal and MW dielectric heating. In all cases, multiple cycloadditions took place to give a triazole-linked tetra-C-galactosyl-calix[4]arene in up to 90% yield. The [C(8)dabco][N(CN)(2)] ionic liquid was also used to perform the multiclick reactions with propargyl O-lactoside and S-sialoside.