Hydrochloric Acid → N-[3-[3-(hydroxymethylidene)-2-oxo-1H-indole-6-carbonyl]phenyl]thiophene-2-carboxamide

Participants

Reaction Conditions

Reaction Steps

Thiophene-2-carboxylic acid [3-(2-oxo-2,3-dihydro-1H-indole-6-carbonyl)-phenyl]-amide (1.27 g, 3.504 mmol) and ethyl formate (0.85 mL, 10.52 mmol) were dissolved in anhydrous ethanol (10 mL). The resulting solution was treated in dropwise fashion with a 21 wt % solution of sodium ethoxide in ethanol (3.90 mL, 10.45 mmol). This reaction mixture was heated at 78° C. for 1 h, producing a black oil. Subsequently, the reaction mixture was cooled to room temperature, and then the reaction pH was adjusted to pH 1 with dropwise addition of 1M HCl(aq) causing the formation of a pale orange precipitate. The suspension was filtered yielding an orange solid as the pure Thiophene-2-carboxylic acid [3-(3-hydroxymethylene-2-oxo-2,3-dihydro-1H-indole-6-carbonyl)-phenyl]-amide (0.971 g, 2.487 mmol, 71%).

Provenance & Evidence