反应详情

温度

5 °C

2-Amino-9-(3,5-di-O-tert-butyldimethylsilyl-2-O-valeryl-β- D-arabinofuranosyl)-6-methoxy-9 H-purine (1.4 g, 2.3 mmol) was taken up in tetrahydrofuran (THF, 40 mL) and cooled in an ice bath to 5° C. Acetic acid (0.06 mL, 10 mmol) was added, followed by tetrabutylammonium fluoride (TBAF) as a 1M solution in THF (10 mL, 10 mmol). After 18 hours at 5° C., the reaction mixture was diluted with CCHl3 (40 mL) and passed through a pad of silica gel (230-400 mesh, 5×5 cm) with 1:1 acetone:CHCl3 (500 mL).The filtrate was concentrated and purified on a Chromatotron fitted with a 4 mm rotor and eluted with neat ethyl acetate. Pure product was obtained from the column as a white foam 0.72 g (78%) after drying and was shown to be the desired 2'-O-valeryl derivative: m.p.: 83°-86° C. (uncorrected); UV λmax (.di-elect cons.): pH=7.00: 280.0 nm (7,800), 247.8 nm (8,400); 0.1N HCl: 278.6 (8,000), 248.7 (7,400); 0.1N NaOH: 286.2 (7,600), 244.9 (7,200); MS (EI): m/z 381 (C16H23N5O6), 351 (C15H21N5O5), 292 (C13H:8N5O3), 279 (C11H13N5O4), 249 (C10H11N5O3), 217 (C10H17O5), 194 (C7H8N5O2), 165 (C6H7N5O), 135 (C5H5N4), 85 (C5H9O). IR (KBr) 1745.2, 1613.3 and 1588.7 cm-1. 1H-NMR (Me2SO-d6): δ7.93 (s, 1 H, H-2), 6.46 (brs, 2 H, NH2), 6.26 (d, 1 H, H-1', J=5.9 Hz), 5.79 (d, 1 H, 3'-OH, J=5.1 Hz), 5.23 (t, 1 H, H-2', J=5.8 Hz), 5.02 (t, 1 H, 5'-OH, J=5.6 Hz), 4.36 (ddd, 1 H, H-3', J3',3'-OH =5.1 Hz, J2',3' =5.7 Hz, J3',4' =5.8 Hz), 3.93 (s, 3 H, Pur-OCH3), 3.83-3.78 (m, 1 H, H-4'), 3.68-3.61 (m, 2 H, H-5'), 2.09 (dt, 1 H, C(O)CH2, J=7.5 Hz, J=15 Hz), 1.93 (dt, 1 H, C(O)CH2, J=7.5 Hz, J=15 Hz), 1.30-0.90 (m, 4H, --CH2CH2 --), 0.65 (t, 3 H, --CH3, J=7 Hz).

1. additionthe reaction mixture was diluted with CCHl3 (40 mL)
2. concentrationCHCl3 (500 mL).The filtrate was concentrated
3. custompurified on a Chromatotron
4. customfitted with a 4 mm rotor
5. washeluted with neat ethyl acetate