反应详情

The anomeric mixture of 20 (0.132 g, 0.49 mmol) in a steel bomb was stirred with 20 mL 40% methylamine in water at 80° C. overnight. After solvent removal in vacuo, the residue was purified by preparative TLC with 9:1 chloroform/methanol to give 100 mg (77%) of the anomeric mixture. The anomers were partially separated by a Dowex 1×4 (--OH) column with 10% aqueous methanol to give 37 mg of impure β anomer which was recrystallized from hexane-ethyl acetate to afford 22.5 mg of pure β anomer by HPLC; mp. 131°-134° C.; FAB MS 266 (M +H)+ ; 1H NMR (DMSO-d6) δ 8.4 (s, 1, H-2), 8.2 (s, 1, H-8), 7.7 (brs, 1, NH), 6.2 (m, 1, i'-H), 5.15 (m, 1, 5'-OH), 3.75 (m, 1, 5'-H), 3.6 (m, 2, 4'-H, 5'-H), 2.95 (s, 3, CH3), 2.4 (m, 2, 4'-H's), 2.15 (m, 1, 3'-H), 2.0 (m, 1, 3'-H).

1. customAfter solvent removal in vacuo
2. customthe residue was purified by preparative TLC with 9:1 chloroform/methanol