反应详情

4-Bromo-3-methyl-thiophene-2-carboxylic acid methyl ester (3.0 g, 12.8 mmol), example 31-a, N-bromosuccinimide (2.33 g, 13.1 mmol), and benzoyl peroxide (310 mg, 1.28 mmol) were suspended in 32 mL of benzene and heated at reflux temperature for 16 hours. The reaction mixture was cooled and diluted with ethyl acetate. The reaction mixture was washed successively with saturated bicarbonate solution, brine, saturated ammonium chloride solution, and brine. The organic solvent was dried, filtered, and concentrated. The crude product was purified by flash chromatography eluting from silica gel with a gradient of 0-40% ethyl acetate in hexanes to produce 2.28 g of a yellow solid. NMR (CDCl3, 200 MHz): δ=7.48 (s, 1H), 4.91 (s, 2H), and 3.94 (s, 3H).

1. temperatureheated
2. temperatureat reflux temperature for 16 hours
3. temperatureThe reaction mixture was cooled
4. washThe reaction mixture was washed successively with saturated bicarbonate solution, brine, saturated ammonium chloride solution, and brine
5. customThe organic solvent was dried
6. filtrationfiltered
7. concentrationconcentrated
8. customThe crude product was purified by flash chromatography
9. washeluting from silica gel with a gradient of 0-40% ethyl acetate in hexanes