反应详情

温度

-60 °C

To a −60° C. solution of 2,6-dimethyl pyridine (48 mL, 457 mmol) in tetrahydrofuran (800 mL) was added n-butyl lithium (183 mL, 2.5 M in hexanes, 457 mmol) over 30 minutes. The resulting red solution was stirred at −60° C. for 1 hour, and then treated with a solution of benzo[1,3]dioxole-5-carboxylic acid methoxy-methyl-amide of Step A (415 mmol) in tetrahydrofuran (200 mL) over 1 hour. The resulting reaction mixture was slowly warmed to −20° C. over 3 hours, and then poured over ice (1 kg). The liquid phase was decanted and the ice was washed with methyl tert-butyl ether (1L). The combined organic extracts were washed with saturated aqueous sodium chloride (3×100 mL), dried with magnesium sulfate and concentrated in vacuo to yield the title compound crude (102 g). Recrystallization from toluene yielded the title compound as a yellow solid (57 g, 49% over two steps).

1. customThe resulting reaction mixture
2. temperaturewas slowly warmed to −20° C. over 3 hours
3. customThe liquid phase was decanted
4. washthe ice was washed with methyl tert-butyl ether (1L)
5. washThe combined organic extracts were washed with saturated aqueous sodium chloride (3×100 mL)
6. dry with materialdried with magnesium sulfate
7. concentrationconcentrated in vacuo