Widely used in solid-phase oligonucleotide synthesis, this compound serves as a key building block for incorporating modified nucleosides into DNA strands. The 2-thio modification enhances nuclease resistance and improves binding affinity to complementary RNA, making it valuable in antisense technology and therapeutic oligonucleotide development. The DMT (dimethoxytrityl) group enables stepwise chain elongation by protecting the 5'-hydroxyl during synthesis, while the phosphoramidite moiety allows efficient coupling to the growing oligonucleotide chain. The N4-toluoyl group stabilizes the base during synthesis and is later removed under standard deprotection conditions. Its primary application lies in the production of modified antisense oligonucleotides, siRNA, and diagnostic probes where enhanced stability and specificity are required.