反应详情

温度

-78 °C

To a solution of 4-azido-7-(2-methyl-4-nitro-pyrazol-3-yl)oxepan-3-one (Intermediate 55) (1 g, 3.57 mmol) in dry THF (25 mL) under nitrogen cooled to −78° C. was added L-selectride (1 M in THF, 4.3 mL, 4.3 mmol) and the mixture was stirred at −78° C. for 45 min. The mixture was allowed to warm to room temperature and water (10 mL) was added. The solvents were removed under reduced pressure and the residue was dissolved in EtOAc (100 mL). The organic layer was washed with water (40 mL) and brine (40 mL), dried over Na2SO4 and concentrated under reduced pressure. Purification via silica gel column chromatography (0-60% EtOAc/isohexane) gave racemic 4-azido-7-(1-methyl-4-nitro-1H-pyrazol-5-yl)oxepan-3-ol (relative stereochemistry as shown above) as a yellow oil (580 mg, 58%). 1H NMR (400 MHz, CDCl3) δ 8.02 (s, 1H), 5.63 (dd, J=10.6, 3.5 Hz, 1H), 4.21-4.14 (m, 3H), 4.01 (s, 3H), 3.69-3.58 (m, 1H), 2.45-2.33 (m, 1H), 2.27-2.08 (m, 2H), 2.01-1.84 (m, 2H).

1. temperatureto warm to room temperature
2. customThe solvents were removed under reduced pressure
3. dissolutionthe residue was dissolved in EtOAc (100 mL)
4. washThe organic layer was washed with water (40 mL) and brine (40 mL)
5. dry with materialdried over Na2SO4
6. concentrationconcentrated under reduced pressure
7. customPurification via silica gel column chromatography (0-60% EtOAc/isohexane)