3066-86-2

65-46-3

3066-86-2

The general procedure for the synthesis of 4-amino-5-bromo-1-((2R,3R,4S,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)pyrimidin-2(1H)-one from cytidine was as follows: using a typical method of bromination of unprotected nucleosides, 1,3-dibromo-5,5-dimethylglycolactonium (DBH, 323 mg, 1.13 mmol ) was added to a stirred solution of cytidine (1d, 500 mg, 2.05 mmol) in N,N-dimethylformamide (DMF, 5 mL). The reaction mixture was stirred at room temperature for 20 min or monitored by thin layer chromatography (TLC) until the starting material completely disappeared and a less polar product was formed. Subsequently, the volatile solvent was evaporated under reduced pressure and the residue was co-evaporated with acetonitrile (MeCN) to remove the residual DMF.The resulting light-colored solid was recrystallized from hot acetone to give the target product 2d (500 mg, 75% yield) as colorless crystals with physicochemical properties consistent with those reported in the literature.