Azobisisobutyronitrile → Methyl 3-(bromomethyl)thiophene-2-carboxylate

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Reaction Steps

A 1-L single-neck round-bottomed flask equipped with a magnetic stirrer, reflux condenser and nitrogen inlet was purged with nitrogen and charged with 116b (5.00 g, 32.0 mmol), N-bromosuccinimide (5.70 g, 32.0 mmol) and carbon tetra-chloride (300 mL). The solution was heated to 70° C. (oil bath temperature), and 2,2′-azobisisobutyronitrile (526 mg, 3.20 mmol) was added. The resulting mixture was refluxed for 3 h. After that time, the mixture was cooled to room temperature and filtered. The filter cake was washed with carbon tetrachloride (2×50 mL). The filtrate was diluted with ethyl acetate (300 mL) and washed with water (40 mL), saturated aqueous sodium bicarbonate (40 mL) and brine (40 mL). The organic layer was dried over sodium sulfate and concentrated under reduced pressure to afford a quantitative yield (7.50 g) of 116c as a colorless oil: 1H NMR (300 MHz, CDCl3) δ 7.39 (d, 1H, J=5.0 Hz), 7.11 (d, 1H, J=5.1 Hz), 4.85 (s, 2H), 3.83 (s, 3H).

Provenance & Evidence