13276-52-3

3056-18-6

13276-52-3

Under nitrogen protection, 450 mL of fully acetyl-protected 2,6-dichloropurine riboside (0.1 mol) and anhydrous methanol were added to a three-necked flask equipped with a dropping funnel, stirred until the system was completely clarified, and cooled to -10°C. The reaction was carried out by TLC. Acetyl chloride (1.2 moles) was added slowly dropwise and after completion of the dropwise addition, the reaction was continued for 1.5 h. The progress of the reaction was monitored by TLC. After completion of the reaction, solid potassium carbonate was added to the system in batches until the pH reached 7-8 and the reaction mixture was filtered. The filtrate was concentrated to dryness, appropriate amount of water was added and extracted three times with 250 mL of ethyl acetate. The organic phases were combined, dried over anhydrous sodium sulfate, filtered and the filtrate concentrated to dryness. Crystallization was carried out by adding 140 mL of isopropanol to give 27.3 g of 2,6-dichloropurine riboside as a white solid in 85% yield.