1,2,3-Triazoles as leaving groups in purine chemistry: a three-step synthesis of N6-substituted-2-triazolyl-adenine nucleosides and photophysical properties thereof

A novel three-step approach for the synthesis of N6-substituted-2-(1,2,3-triazol-1-yl)-adenine nucleosides is described. 2,6-Bis-(1,2,3-triazol-1-yl)purine nucleosides are obtained, which undergo regioselective nucleophilic aromatic substitution with amines at C(6). Thus, 1,2,3-triazoles are shown to be good leaving groups in purine chemistry. The title compounds exhibit interesting levels of fluorescence with quantum yields of up to 53%.