Recent Developments in the Synthesis and Applications of C5-Substituted Pyrimidine Nucleosides and Nucleotides

C5-position in pyrimidine nucleosides and nucleotides is an invaluable anchor point for tagging diverse kind of labels like haptens, dyes and signaling molecules. Oligonucleotides with such C5-modified pyrimidine nucleosides and nucleotides are being used in molecular genetics and next generation nucleic acid sequencing as indispensable diagnostic tools. In view of their requirement in a wide range of primers and probes, chemistry synthesis and manufacture of C5-modified substituted pyrimidines had elicited continued interest over the last several decades. These diverse classes of molecules also have pharmaceuticals significance. The objective of this review is to capture the recent strategies available to synthesize C5-modified pyrimidine nucleosides and nucleotides that include organometallic, "Click" and photochemistry.