Used in solid-phase oligonucleotide synthesis, this phosphoramidite building block enables the site-specific incorporation of a modified cytidine residue into DNA strands. The 5-bromo substitution allows for downstream crosslinking or functionalization, useful in probe development and nucleic acid labeling. The N4-benzoyl group protects the cytosine base during synthesis, while the 5′-O-DMT group ensures stepwise chain elongation by reversible protection. The 3′-CE phosphoramidite moiety facilitates efficient coupling to the growing oligonucleotide chain on solid support. Commonly applied in the production of antisense oligonucleotides, molecular probes, and modified primers for diagnostic and therapeutic research.