Facile preparation of DNA-tagged carbohydrates

We report here that unprotected carbohydrates (maltose, lactose, cellobiose, and maltoheptaose) can be attached to the aminoalkylated oligonucleotides under mild reductive-amination conditions (aqueous borate buffer, pH 8.0, NaBH3CN, 60 °C) without notable side reactions. Quadruplex-forming G-rich oligonucleotide, 5′-aminoalkyl d(TGGGGT), is glycosylated with maltoheptaose to afford a novel DNA-assisted tetrasaccharide cluster motif.