Synthesis of 2-Amino-4-Fluoropyridine-C-Nucleoside Phosphoramidite for Incorporation into Oligonucleotides

Straightforward and efficient methods for the synthesis of 2-amino-4-fluoropyridine-C-nucleoside (d^F P) and the solid-phase synthesis of oligodeoxynucleotides containing d^F P using a phosphoramidite are described. The synthesis of d^F P is achieved by cross-coupling between a nucleobase (2-amino-4-fluoro-3,5-diiodopyridine) and sugar moieties. Its 3'-O-phosphoramidite is obtained by deiodination, 5'-O-protection, and 3'-O-phosphitilation in three steps. The phosphoramidite unit is compatible for the synthesis of oligonucleotides on solid-phase according to conventional phosphoramidite chemistry. The 2-amino-4-fluoropyridine-C-nucleoside moiety incorporated into the oligodeoxynucleotide reacts with a Cys residue in the catalytic site of DNA cytosine-5-methyltransferase (DNMT). It is apparent that 2-amino-4-fluoropyridine-C-nucleoside would be utilized in DNA-protein crosslink technology. This protocol describes the importance of solid-phase synthesis to obtain novel pyridine-C-nucleoside analogues and its incorporation into oligodeoxynucleotides in a short period of time. © 2019 by John Wiley & Sons, Inc.