反应详情

To a stirred solution of 31 (0.4 g, 2.6 mmol) and (S)-3-methoxy-pyrrolidine (0.4 g, 3.2 mmol) in dichloromethane (10 mL) was added acetic acid (0.01 mL, 0.25 mmol). After 30 minutes, sodium triacetoxyborohydride (1.1 g, 5.3 mmol) was added to the above mixture and stirred at rt for 15 minutes. The reaction mixture was diluted with water (10 mL), treated with saturated NaHCO3 solution to get pH˜8 and extracted with dichloromethane (2×20 mL). The combined organic layers were washed with brine (50 mL), dried (Na2SO4) and evaporated. The crude compound was purified by silica gel flash chromatography, eluting with 2% MeOH/DCM to afford 32 (0.25 g, 40%) as a liquid. Rf: 0.3 (5% MeOH/DCM); (m/z): 238 [MH]+; 1H NMR (400 MHz, DMSO-d6): δ 9.28 (1H, d, J=2.8 Hz), 8.59-8.56 (1H, m), 7.71 (1H, d, J=8.8 Hz), 3.93-3.80 (3H, m), 3.16 (3H, s), 2.73-2.62 (2H, m), 2.56-2.53 (1H, m), 2.50-2.47 (1H, m), 2.06-2.02 (1H, m), 1.72-1.65 (1H, m).

1. customto get pH˜8
2. extractionextracted with dichloromethane (2×20 mL)
3. washThe combined organic layers were washed with brine (50 mL)
4. dry with materialdried (Na2SO4)
5. customevaporated
6. customThe crude compound was purified by silica gel flash chromatography
7. washeluting with 2% MeOH/DCM