Practical halogenations of nucleosides using tetrabutylammonium peroxydisulfate

Direct halogenation of a wide range of acetylated pyrimidine and purine nucleosides was achieved with high regioselectivity in good yields using tetrabutylammonium peroxydisulfate 1. Treatment of protected nucleosides with HCl/DMF or inorganic salts such as LiCl or NaCI in MeCN/AcOH in the presence of 1 gave the corresponding chlorinated nucleosides and bromination was achieved with N-bromosuccinimide in MeCN in the presence of 1.