The 7-nitroindole nucleoside as a photochemical precursor of 2 '-deoxyribonolactone: Access to DNA fragments containing this oxidative abasic lesion

On the basis of molecular modeling studies, the 7-nitroindole nucleoside 1 was selected as a suitable photochemical precursor for photochemical genera tion of the C1' deoxyribosyl radical under irradiation, which led to 2'-deo xyribonolactone. The nitro-indole nucleoside derivatives 1a and 1b were pre pared and their conformation was determined by X-ray crystallography and NM R spectroscopy. The photo-reaction of these nucleosides gave the correspond ing deoxyribonolactone derivatives efficiently, with release of 7-nitrosoin dole. This reaction was successfully applied to synthesis of oligonucleotid es containing the deoxyribonolactone lesion.