The effect of the glycosylation position on the base pairing and supramolecular structure of the 5′-deoxyribosyl Janus-type AT nucleosides

• A rare regioisomer of Janus-type AT nucleosides was synthesized via Vorbrueggen reaction.
• A novel pair motif was revealed within the single crystal structure.
• Micro-flower, nanobundles and laminated supramolecular were formed by different regioisomers.
• CD, UV, PXRD and SEM were used to fully investigate its distinctive structure.

The intrinsic structural diversity of the nucleosides is one of the essential properties for their wide participation in myriads of chemical or biochemical processes. Two unique regio-isomeric Janus-type AT nucleosides with the 5′-deoxyribose attached on N1 or N3 position has been synthesized through Vorbrueggen or transglycosylation reactions. These two isomers display different supramolecular morphologies in solution state from their N8 glycosylated counterpart. The underneath structural details of the N3 glycosylated isomer were revealed by the single-crystal X-ray analysis. In addition to a novel base pair pattern was identified which is entirely different from the reverse Watson-Crick base pair adopted by its N8 isomer, an interesting water-filled columnar nanotuble-like structure was also found in its solid state. This study not only enriches the structural varieties of AT Janus-type nucleosides, but also provides specific information concerning the effect of the sugar glycosylation position on the properties of these new type of pyrimido[4,5-d]pyrimidine nucleosides.

Two unique regio-isomeric Janus-type AT nucleosides with the 5′-deoxyribose attached to N1 or N3 has been synthesized. A novel base pair and an interesting water-filled nanotube-like supramolecular structure were revealed.Figure optionsDownload as PowerPoint slide