Synthesis and incorporation into DNA fragments of the artificial nucleobase, 2-amino-8-oxopurine

The nucleoside 2-amino-9-(2-deoxy-β-d-ribofuranosyl)-7,8-dihydro-8-oxo-purine (dJ) was obtained in eight steps from 2′-deoxyguanosine. The appropriate protected phosphoramidite was synthesized and incorporated into DNA oligonucleotides. The thermal stability of heteroduplexes containing 2-amino-8-oxopurine (J) was investigated by UV-thermal denaturation experiments. The results obtained can be interpreted by the base pairing schemes involving the two edges of dJ depending on the anti and syn orientations.