Hydrochloric Acid → 4-Fluorothieno[2,3-c]pyridine-2-carboxylic acid

Participants

Reaction Steps

To a solution of methyl 4-fluorothieno[2,3-c]pyridine-2-carboxylate (0.942 g, 4.46 mmol) in THF (23 mL) was added a solution of lithium hydroxide monohydrate (0.384 g, 9.14 mmol) in water (23 mL). Methanol (2.8 mL) was then added until the solution was transparent. The reaction mixture stirred 2 h at room temperature. The reaction was then adjusted to pH ˜4 by addition of 2 N aqueous HCl, causing formation of a white precipitate. THF and methanol were removed by rotary evaporation, and then the residual solid was collected by vacuum filtration, washing with water (2×25 mL). The collected white solid was dried in an oven at 50° C. to afford 765 mg (87%) of the title compound. 1H NMR (400 MHz, DMSO-d6): δ 14.15 (br. s., 1 H), 9.23 (s, 1 H), 8.54 (s, 1 H), 8.14 (s, 1 H); MS (ESI): 198.05 [M+H]+; HPLC tR=2.40 min (ZQ3, polar—4 min).

Provenance & Evidence