反应详情

To a solution of the β anomer 17 (0.15 g, 0.32 mmol) in THF (25 mL) was added tetrabutylammonium fluoride 1M in THF (0.35 mL, 0.35 mmol, 1.1 eq) and the reaction was allowed to stir at room temperature until TLC indicated the disappearance of starting material (30 min). The reaction mixture was concentrated under reduced pressure and the residue purified by preparative TLC using 12% MeOH/CHCl3 as development solvent to give 0.055 g (75%) of 3 from ethyl ether/MeOH (trace) as a white crystalline solid. [α]23D =-121.6 (c 1.1, MeOH) (for the S,R isomer 2 [α]23D =120.96 (c 1.06, MeOH)); 1H NMR: ((CD3)2SO) δ 3.03 (dd, J5,4a =4.4 Hz, J4a,4b =11.86 Hz, 1 H, 4a-H), 3.43 (dd, J5,4b =5.3 Hz, J4a,4b =11.86 Hz, 1 H, 4b-H), 3.80 (app t on D2O exchange goes to d, J2,2-CH2-OR =4.17 Hz, 2 H, 2-CH2 -OH), 5.27 (t, J2-CH2,OH =4.6 Hz, 1 H, 2-CH2OH), 5.22 (t, J2,2-CH2-OH =4.17 Hz, 1 H, 2-H), 5.88 (d, J5,6 =7.47 Hz, 1 H, H-5), 6.21 (app t, J=5.05 and 4.84 Hz, 1 H, 5-H), 7.19 (bs, 2 H, NH2), 7.89 (d, J5,6 =7.47 Hz, 1 H, H-6).

1. customthe disappearance of starting material (30 min)
2. concentrationThe reaction mixture was concentrated under reduced pressure
3. customthe residue purified by preparative TLC