Synthesis of pyridinone ribonucleoside 3′-O-phosphoramidites and their incorporation into oligoribonucleotides

Protected pyridin-2- and pyridin-4-one ribonucleosides 3 and 9 were synthesized using a one-pot reaction of silylated bases with (2) in the presence of CF3SO3SiMe3. The nucleosides were converted in 4 steps into 3′-O-phosphoramidites 7 and 11 which were incorporated into hammerhead ribozyme substrates using solid-phase phosphoramidite chemistry.