Solution and solid-phase synthesis of sialooligomers

Abstract

The solution phase synthesis of amide-linked derivatives of sialic acid has been achieved. The N-acetyl group on sialic acid was removed via N-BOC protection of the lactam and ensuing displacement with NaOMe. Subsequent removal of the BOC protecting group group with TFA resulted in the free amine which was then coupled with the free acid using BOP, Hunig's base, and NMP. These compounds may afford greater solubility than previously synthesized amide-linked carbohydrate amino acids and may give rise to novel helical structures. The efficacy of using monomer units of sialic acid in solid-phase oligomer synthesis has also been studied. The peracetylated FMOC-protected derivative of sialic acid which has been shown to be amenable to solid-phase synthesis has also been synthesized. However, difficulties were encountered during the solid-phase synthesis of these sialooligomers due to transacetylation of the acetate groups to re-form the N-acetyl bond.