Hydrochloric Acid → 5-ethyl-N-[3-[3-(hydroxymethylidene)-2-oxo-1H-indole-6-carbonyl]phenyl]-1-methylpyrazole-3-carboxamide

Participants

Reaction Conditions

Reaction Steps

5-Ethyl-1-methyl-1H-pyrazole-3-carboxylic acid [3-(2-oxo-2,3-dihydro-1H-indole-6-carbonyl)-phenyl]-amide (0.240 g, 0.6179 mmol) and ethyl formate (0.148 mL, 1.84 mmol) were dissolved in anhydrous ethanol (6 mL). The resulting solution was treated in dropwise fashion with a 21 wt % solution of sodium ethoxide in ethanol (1.2 mL, 3.21 mmol). This reaction mixture was heated at 78° C. for 0.5 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 tan precipitate. The suspension was filtered and the solids were washed with 0° C. EtOH to afford the pure 5-Ethyl-1-methyl-1H-pyrazole-3-carboxylic acid [3-(3-hydroxymethylene-2-oxo-2,3-dihydro-1H-indole-6-carbonyl)-phenyl]-amide (0.2187 g, 0.525 mmol, 85%).

Provenance & Evidence