Efficient synthesis of extended guanine analogues designed for recognition of an A·T inverted base pair in triple helix based-strategy

We report herein an efficient synthesis of new nucleosides N1, N2, and N3 as extended guanine analogues, derived from aminobenzimidazole and thymine or 5-substituted uracil. These nucleosides were devised for the recognition of an A·T inverted base pair by three hydrogen bonds, in triple helix-based technology.