反应详情

Ethyl 4-bromo-5-methyl-1H-pyrrole-2-carboxylate (Intermediate 187, 2.87 g, 12.4 mmol) was dissolved in dry DMF (30 ml), N-chlorosuccinimide (1.66 g, 12.4 mmol) was added and resulting mixture was stirred at room temperature over night, more N-chlorosuccinimide (0.83 g, 6.2 mmol) was added and the reaction temperature was increased to 35° C., stirred for 4 hours. The mixture was poured into cold sodium hydroxide aqueous solution (2M) (50 ml), extracted with diethyl ether (2×50 ml). The organic phase was then washed with water (20 ml) and brine (20 ml), dried over anhydrous sodium sulfate and purified by column chromatography(hexanes/ethyl acetate, gradient) to give the desired product as a white crystal. (1.2 g).

1. customresulting mixture
2. temperaturethe reaction temperature was increased to 35° C.
3. stirringstirred for 4 hours
4. extractionextracted with diethyl ether (2×50 ml)
5. washThe organic phase was then washed with water (20 ml) and brine (20 ml)
6. dry with materialdried over anhydrous sodium sulfate
7. custompurified by column chromatography(hexanes/ethyl acetate, gradient)