5′-C-Tosyloxyalkylnucleosides. Models for Oligonucleotide Coupling with Nucleophiles
摘要:
5'-C-substituted nucleosides with an hydroxyalkyl chain are synthesized. The stereochemistry of the new stereogenic center is defined. After introduction of a tosyl group, dimer models are prepared to evaluate the conjugation with amines used as nucleophiles.
Uridine5′-monoselenoacetals prepared by the seleno-Pummerer reaction of 5′-deoxy-5′-phenylseleno-uridines were used as substrates for radical-mediated reactions with allyltributyltin. The reaction of the 2′,3′-O-isopropylidene derivative gave cyclized products, 5-allyl-6,5′-cyclonucleosides, whereas those of the 2′,3′-bis-O-(tertbutyldimethylsilyl derivatives underwent the C-Cbondformation at the