appropriate set of protecting groups was optimized including the 4-thio function introduced via 4-triazolyl as the 4-(2-cyanoethyl)thio derivative, and the t-butyldimethyl silyl for 2′ and 3′ hydroxyl protection, enabling efficient synthesis of the phosphoramidite. These protecting groups prevented unwanted side reactions during oligonucleotide synthesis. The utility of the proposed synthetic route was proven