反应详情

As taught by Zhang, W., and Robins, M. J. “Removal of Silyl Protecting Groups from Hydroxyl Functions with Ammonium Fluoride in Methanol” Tetrahedron Lett, 1992, 33, 1177-1180, a solution of 3′,5′-O-(1,1,3,3-tetraisopropyl-1,3-disiloxanyl)-2′-deoxy-L-adenosine 148 (32 g, 65 mmol) and ammonium fluoride (32 g, mmol; Fluka; ref 09742) in methanol (Prolabo; ref 20847.295) was stirred at reflux for 2 hrs (Scheme 5). Silica gel (Merck; ref 1.07734.2500) was added and the mixture was carefully evaporated to give a white powder. This powder was added on the top of a silica column, which was eluted with dichloromethane (Merck; ref 1.06050.6025)/methanol 9/1. The appropriate fractions were combined and evaporated to give a white powder, which was crystallized from ethanol 95 (Prolabo; ref 20823.293) to yield 12.1 g of product (75%): mp 189-190° C. (EtOH 95) (identical to commercial 2′-deoxy-D-adenosine); 1H NMR (200 MHz, DMSO-D6): δ 8.35 and 8.14 (2s, 2H, H2 and H8), 7.34 (s1, 2H, NH2), 6.35 (dd, 1H, H1′, J 6.1 Hz, J 7.85 Hz), 5.33 (d, 1H, OH2′, J 4.0 Hz), 5.28 (dd, 1H, H3′, J 4.95 Hz; J 6.6 Hz), 4.42 (m, 1H, OH5′), 3.88 (m, 1H, H4′), 3.63-3.52 (m, 2H, H5′a and H5′b), 2.71 (m, 1H, H2′a), 2.28 (m, 1H, H2′b). (identical to commercial 2′-deoxy-D-adenosine); αD +26° (c 0.5 water) (commercial 2′-deoxy-D-adenosine −25° (c 0.5 water)); UV λmax 260 nm (ε 14100) (H2O); Mass analysis (FAB+, GT) m/z 252 (M+H)+, 136 (BH2)+.