反应详情

To a solution of 1-methyl-4-nitro-5-(2,3,4,7-tetrahydrooxepin-2-yl)pyrazole (1.00 g, 4.74 mmol) in DCM (25 mL) was added m-CPBA (70-75%, 1.75 g, 7.11 mmol) and the reaction mixture was stirred at room temperature for 18 hr. The reaction mixture was diluted with DCM (50 mL), washed with saturated aqueous NaHCO3 (50 mL), water (50 mL) and brine (50 mL). The organic layer was separated, dried over MgSO4, and concentrated under reduced pressure. Purification via silica gel column chromatography (0-30% EtOAc/isohexane) gave racemic 5-(5,8-dioxabicyclo[5.1.0]octan-4-yl)-1-methyl-4-nitro-pyrazole as a colourless solid (490 mg, 43%). 1H NMR (400 MHz, CDCl3) δ 8.22-7.87 (m, 1H), 5.07 (d, J=9.9 Hz, 1H), 4.50 (dd, J=14.5, 3.1 Hz, 1H), 4.05 (s, 3H), 3.93 (d, J=14.4 Hz, 1H), 3.35 (t, J=4.5 Hz, 1H), 3.13 (t, J=3.6 Hz, 1H), 2.55-2.47 (m, 1H), 2.31-2.21 (m, 1H), 2.16-2.04 (m, 1H), 1.79 (dd, J=14.4, 1.8 Hz, 1H).

1. washwashed with saturated aqueous NaHCO3 (50 mL), water (50 mL) and brine (50 mL)
2. customThe organic layer was separated
3. dry with materialdried over MgSO4
4. concentrationconcentrated under reduced pressure
5. customPurification via silica gel column chromatography (0-30% EtOAc/isohexane)