Synthesis of Azanucleosides by Anodic Oxidation in a Lithium Perchlorate-Nitroalkane Medium and Diversification at the 4′-Nitrogen Position

Azanucleosides, in which the 4'-oxygen atom has been replaced with a nitrogen atom, have drawn much attention owing to their anticancer and antivirus activity, and tolerance towards nucleases. However, the traditional synthetic strategy requires multiple steps and harsh conditions, thereby limiting the structural and functional diversity of the products. Herein we describe the synthesis of azanucleosides by an electrochemical reaction in a lithium perchlorate-nitroethane medium, followed by postmodification at the 4'-N position. N-Acryloyl prolinol derivatives were converted into azanucleosides by anodic activation of the N-alpha-C-H bond. Moreover, the use of nitroethane instead of nitromethane lowered the oxidation potential of the N-acryloyl prolinols and increased the Faradic yield. The prepared azanucleosides were efficiently functionalized at the 4'-N-acryloyl group with a lipophilic alkanethiol and a fluorescent dye by conjugate addition and olefin cross-metathesis, respectively.