Highly Efficient Method for C-5 Halogenation of Pyrimidine-Based Nucleosides in Ionic Liquids

A novel, highly efficient, convenient, and benign meth- odology for C-5 halogenation of pyrimidine-based nucleosides has been developed using N-halosuccinimides as halogenating reagents without using any catalyst in ionic liquid medium. The ionic liquids were successfully recovered and reused for all the reactions.