The general procedure for the synthesis of (2R,3S,4R,5R)-2-(hydroxymethyl)-5-(6-((2-(methylthio)ethyl)amino)-2-((3,3,3-trifluoropropyl)thio)-9H-purin-9-yl)tetrahydrofuran-3,4-diol, using the compound (CAS:163706-57-8) as a raw material, is as follows: the crude obtained in Example 38 was reacted with the crude product (60.3 g) was co-dissolved with potassium carbonate (199 g, 1.44 mol) in 600 mL of isopropanol, heated to reflux and the reaction was maintained for 2 hours. Upon completion of the reaction, the solvent was removed by distillation under reduced pressure to give a concentrate. To the concentrate, 300 mL of water was added and the pH was adjusted to about 7 using acetic acid with continuous stirring for 0.5 hours. Subsequently, the reaction mixture was filtered and the solid product was collected and dried to give a final 33.8 g of pale yellow solid product. The overall yield of this three-step synthetic process was 75% (based on the compound of formula (10)) and the product purity was 97.9% as analyzed by high performance liquid chromatography (HPLC).
