Used in solid-phase oligonucleotide synthesis, this phosphoramidite enables the site-specific incorporation of nebularine, a purine nucleoside analog, into RNA strands. The 2′-O-tert-butyldimethylsilyl group provides 2′-hydroxyl protection, ensuring regioselective coupling and enhancing RNA stability during synthesis. The 5′-O-DMT (dimethoxytrityl) group allows for stepwise chain elongation and real-time monitoring of coupling efficiency through colorimetric detection. As a CE (cyanoethyl) phosphoramidite, it supports efficient phosphite triester bond formation under standard DNA/RNA synthesizer conditions. This compound is particularly valuable in the preparation of modified antisense oligonucleotides, siRNA, and functional RNA probes where controlled placement of ribonucleoside analogs is required for studying RNA structure, function, or therapeutic activity.