Used in solid-phase oligonucleotide synthesis as a protected deoxycytidine phosphoramidite building block. The 4,4'-dimethoxytrityl (DMT) group protects the 3'-hydroxyl during chain assembly, enabling stepwise addition of nucleotides. The cyanoethyl group shields the phosphate moiety in the phosphoramidite, preventing side reactions and ensuring efficient coupling. After each coupling step, the DMT group is selectively removed under mild acidic conditions to expose the 3'-OH for the next nucleotide addition. The N4-acetyl protection on the cytosine base prevents unwanted alkylation and ensures correct base pairing. This compound is essential for the automated synthesis of DNA sequences used in PCR primers, probes, gene fragments, and other molecular biology applications requiring high purity and accuracy.