反应详情

A solution of 11 (0.315 g, 0.62 mmol), acetic acid (30 μL, 0.63 mmol) and tetrabutylammonium fluoride (1 M in THF, 0.65 mL, 0.65 mmol) in 3 mL THF was stirred for 10 minutes under nitrogen. The solvent was removed in vacuo and the residue flash chromatographed with dichloromethane followed by 19:1 chloroform/methanol to give 0.164 g (98%) of the anomers. The anomers were separated by centrifugal chromatography with 19:1 chloroform/methanol: yield of β-anomer 10 mg; mp. 125°-128° C.; [α]D25 +2.5° (c=0.1 CH3OH); FAB MS 271 (M+H)+ ; 1H NMR (CDCl3) δ 9.0 (s, 1, H-2), 8.8 (s, 1, H-8), 6.3 (m, 1, 5'-OH), 3.8 (m, 1, 5'-H), 3.65 (m, 2, 4'-H, 5'-H), 2.6 (m, 1, 2'-H), 2.45 (m, 1, 2'-H), 2.2 (m, 1, 3'-H), 2.0 (m, 1, 3'-H).

1. customThe solvent was removed in vacuo
2. customthe residue flash chromatographed with dichloromethane
3. customto give 0.164 g (98%) of the anomers
4. customThe anomers were separated by centrifugal chromatography with 19:1 chloroform/methanol