title: Ring-closing metathesis and glycosylation reactions: synthesis and biophysical studies of polyether-linked carbohydrate-based macrocyclic nucleosides.
abstract: Bis-, tris-, and tetrakisuracil-substituted 12-, 13-, 17-, and 21-membered macrocyclic nucleoside analogues with polyether linkages, including C2-symmetric molecules, have been synthesized through coupling of two appropriately allylated sugar derivatives, derived from D-glucose, followed by a sequential ring-closing metathesis reaction using Grubbs catalysts, double-bond reduction, and nucleoside base insertion under Vorbrüggen reaction conditions. Spectroscopic studies on the interaction of these nucleoside analogues with small molecules, such as the alkaloids berberine and palmatine and the DNA intercalator ethidium bromide, revealed a change in the absorbance and fluorescence of the small molecules suggesting the potential use of these nucleoside molecules as a carrier of small molecules in biological systems. Circular dichroism studies indicated that the complexes of the nucleosides with small molecules undergo aggregation/self-organization. This has been further evidenced by a SEM experiment showing the binding of berberine with one of the nucleoside derivatives, which confirms the occurrence of secondary structure reorganization.
authors.affiliation: Chemistry Division, CSIR-Indian Institute of Chemical Biology , 4, Raja S. C. Mullick Road, Jadavpur, Kolkata 700 032, India.
authors.forename: Soumendra Nath
authors.initials: SN
authors.lastname: Das
authors.forename: Richa
authors.initials: R
authors.lastname: Rana
authors.forename: Sabyasachi
authors.initials: S
authors.lastname: Chatterjee
authors.forename: Gopinatha
authors.initials: G
authors.lastname: Suresh Kumar
authors.forename: Sukhendu B
authors.initials: SB
authors.lastname: Mandal
mesh_terms: D002241:Carbohydrates / Q000737:chemistry*; D002942:Circular Dichroism; D004987:Ethers / Q000737:chemistry*; D006031:Glycosylation; D047028:Macrocyclic Compounds / Q000737:chemistry*; D009705:Nucleosides / Q000737:chemistry*
chemical_list: D002241:Carbohydrates; D004987:Ethers; D047028:Macrocyclic Compounds; D009705:Nucleosides