Hydrochloric Acid → 4-(6-Cyano-2-methyl-thieno[3,2-b]pyrrol-4-yl)-2-hydroxybenzoic acid

Participants

Reaction Steps

To a mixed solution of methyl 4-(6-cyano-2-methyl-thieno[3,2-b]pyrrol-4-yl)-2-(methoxymethoxy)benzoate (0.63 g) in tetrahydrofuran (10 mL), ethanol (5.0 mL) and water (5.0 mL) was added lithium hydroxide monohydrate (0.22 g), and the mixture was stirred at room temperature for 4 hours. Then 1 mol/L hydrochloric acid (10.6 mL) was added to the reaction solution and the resulting mixture was stirred at 50° C. for 5 hours. The reaction solution was concentrated under reduced pressure. To the residue was added water. The precipitated solid was collected by filtration, washed with water, and dried under reduced pressure at 50° C. to give the title compound (0.52 g).

Provenance & Evidence