Process Research on the Preparation of DMT Protected 2′-O-Methoxyethylguanosine for Oligonucleotide Synthesis in Therapeutic Applications

An optimized process to synthesize DMT protected 2 ′-O-methoxyethylguanosine is described. A key step involves the enzymatic deamination of a mixture of alkylated products to selectively afford the desired material without resorting to chromatography for purification. This approach was scaled up to kilogram quantities for use in oligonucleotide therapeutics.