Dichloromethane → 2',3'-di-O-acetyl-5'-deoxy-5-fluorocytidine

Participants

Reaction Conditions

Reaction Steps

5-Fluorocytosine (2.42 g, 18.8 mmol) was suspended in toluene (10 ml) and hexyamethyl-disilazane (3.03 g, 18.8 mmol). The mixture was heated at 100° C. overnight. After concentrating the reaction mixture under reduced pressure, methylene chloride (30 ml) and 5-deoxy-1,2,3-tri-O-Acetyl-β-D-ribofuranoside (4) (5.16 g, 18.8 mmol) were added to the residue. Then, anhydrous stannic chloride (4.90 g, 18.8 mmol) was added dropwise to the ice-cooled reaction mixture over a period of 20 min. After stirring the mixture at room temperature for an additional 2 h, sodium bicarbonate (10 g) was added, followed by the dropwise addition of water (20 ml). After stirring the resulting mixture at room temperature overnight, 4% sodium bicarbonate solution was poured into the reaction mixture and stirred for additional 1 h. The mixture was then extracted with water-methylene chloride. The organic layer was collected, dried with Na2SO4, the solvent was removed under reduced pressure to give brown syrup. The residue was then partially purified by silica gel chromatography using CH2Cl2:MeOH (5:1) as an eluent to yield crude target compound (5) (4.455 g, 13.5 mmol, 72%). 1H NMR in DMSO-d6: δ1.34 (d, 3H, J=6.4 Hz, H-5), 2.05, 2.06 (2s, each 3H, OMe), 4.14 (q, 1H, J=5.0 Hz, H-4), 5.10 (t, 1H, J=6.4 Hz, H-2), 5.43 (dd, 1H, J=6.31 Hz, H-3), 5.77 (dd, 1H, J=1.0 Hz, H-1), 7.71 (br s, 1H, N—CH═C—F), 7.97 (br s, 1H, NH), 8.02 (d, 1H, J=7.0 Hz, NH).

Provenance & Evidence