Water → 7-Oxo-4,5,6,7-tetrahydrobenzo[b]thiophene-2-carboxylic Acid

Participants

Reaction Steps

A 25-mL single-neck round-bottomed flask equipped with a magnetic stirrer was purged with nitrogen and charged with 4,5,6,7-tetrahydrobenzo[b]thiophene-2-carboxylic acid (3.00 g, 16.5 mmol), acetic acid (40 mL) and water (40 mL). A solution of ammonium cerium(IV) nitrate (36.1 g, 65.9 mmol) in acetic acid (40 mL) was added dropwise, and the reaction was stirred at room temperature for 1 h. After this time, the reaction mixture was poured into water (200 mL) and extracted with methylene chloride (3×200 mL). The organic extracts were combined, dried over sodium sulfate, filtered and the solvent removed under reduced pressure to afford 16 in 72% yield (2.35 g) as a yellow solid: mp 174-175° C.; 1H NMR (500 MHz, DMSO-d6) δ 13.60 (bs, 1H), 7.68 (s, 1H), 2.86 (t, 2H, J=6.0 Hz), 2.59 (t, 2H, J=6.0 Hz), 2.08 (quintet, 2H, J=6.0 Hz).

Provenance & Evidence