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■ Diversity-Oriented Synthesis of 2-Substituted Purine Nucleosides from Available Nucleosides via the Late-Stage Nitration/Derivatization

Ran Xia,* Li-Jie Liu, Chao Xia, Li-Ping Sun, and Lei-Shan Chen*

*Department of Chemistry and Chemical Engineering, Xinxiang University, East of JinSui Road, XinXiang City, Henan Province, 453003, China

Abstract

A practical synthesis of 2-substituted purine nucleosides was developed in good to excellent yields from readily available nucleosides, such as adenosine, vidarabine and 2′-deoxyadenosine, via the late-stage nitration/derivatization. The C(2)-H bonds of purines were nitrated by 2,2,2-trifluoroacetic anhydride/Bu4NNO3, followed by nucleophilic substitution or hydrogenolysis reduction converting C(2)-NO2 to C(2)-Cl, C(2)-F, C(2)-N, C(2)-O and C(2)-S bonds. This system could tolerate arabinofuranosyl, ribosyl, deoxyribosyl, -OH or -NH2 groups. The clinical drugs, Regadenoson, Cladribine and Fludarabine, and the important naturally occurring nucleosides, spongosine and crotonoside, could be obtained successfully even on 20 g scales, which made this route more attractive for industrial applications.