Dichloromethane → 2-bromo-4H,5H,6H-thieno(2,3-c)pyrrol-6-one

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Reaction Conditions

Reaction Steps

A 250-mL single-neck round-bottomed flask equipped with a magnetic stirrer was purged with nitrogen and charged with 116e (1.87 g, 13.5 mmol), methylene chloride (10 mL), acetic acid (30 mL). The mixture was cooled to 0° C. Bromine (2.30 g, 14.8 mmol) was added dropwise. After the addition was complete, the mixture was stirred for 3 h at 0° C. and then at room temperature for 48 h. After that time, the mixture was partitioned between aqueous saturated sodium bicarbonate (100 mL) and a 20% (v/v) solution of methanol in methylene chloride (100 mL). The layers were separated, and the aqueous layer was extracted with a 20% (v/v) solution of methanol in methylene chloride (3×100 mL). The combined organic layers were dried over sodium sulfate and concentrated under reduced pressure. The residue was purified by column chromatography (silica, 0% to 10% methanol/methylene chloride) to afford a 34% yield (1.01 g) of 116f as an off-white solid: mp 96-97° C.; 1H NMR (300 MHz, CDCl3) δ 7.09 (s, 1H), 6.57 (br s, 1H), 4.37 (s, 2H); MS (ESI+) m/z 217.9 (M+H).

Provenance & Evidence