Synthesis of Biotinylated Multipodal Glycoclusters on a Solid Support

Trivalent glycoconjugates, each bearing a biotin side arm in addition to three different sugar ligands, have been synthesized on a solid support. The conjugates were assembled on an orthogonally protected pentaerythrityl tetramine core that was anchored to the support through a backbone amide linker. Peptide coupling chemistry was applied to elongate three of the branches with beta-alanine and a fully acylated glycosylacetic acid. The fourth branch was levulinoylated and oximated with aminooxy-derivatized D-biotin, followed by acidolytic release into solution. The acyl protecting groups were removed by methoxide-catalyzed transesterification in methanol