Compound 1 (CAS: 73196-87-9, 1.5 g, 3.4 mmol) was dissolved in pyridine (2 mL) followed by addition of ammonia. The reaction mixture was stirred at room temperature for 3 h. The progress of the reaction was monitored by thin layer chromatography (TLC) until it showed complete deprotection. After completion of the reaction, the solvent was evaporated to dryness under reduced pressure. The crude product was purified by recrystallization from water to afford the target product 9-((2R,3R,4S,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-2-(dimethylamino)-1,9-dihydro-6H-purin-6-one in a yield of 0.68 g and 65%. The structure of the product was confirmed by 1H NMR, 13C NMR and mass spectrometry (ES-TOF).1H NMR (DMSO-d6) δ: 3.06 (6H, s, NMe2), 3.48-3.63 (2H, m, 5'-CH2), 3.86 (1H, q, J = 4 Hz, H4'), 4.11 (1H, q, J = 4 Hz, H3' ), 4.50 (1H, q, J = 4 Hz, H2'), 4.91 (1H, t, J = 5.4 Hz, OH5'), 5.15 (1H, d, J = 4.8 Hz, OH3'), 5.38 (1H, d, J = 6.1 Hz, OH2'), 5.71 (1H, d, J = 5.8 Hz, H1'), 5.92 (1H, s, H8 ), 10.69 (1H, bs, NH); 13C NMR δ: 38.1 (NMe2), 61.8 (C5'), 70.7 (C3'), 73.7 (C2'), 85.4 (C4'), 87.0 (C1'), 100.0, 116.4, 136.8 (C8), 151.1, 153.3, 157.7; MS ( ES-TOF) m/z: calculated value 312.13, measured value 312.54.
