Thionyl Chloride → 2-Ethyl-5-methyl-2H-pyrazole-3-carboxylic acid [4-(2-oxo-2,3-dihydro-1H-indol-5-ylmethyl)-phenyl]-amide

Participants

Reaction Conditions

Reaction Steps

A dry 25 mL flask was charged with 2-Ethyl-5-methyl-2H-pyrazole-3-carboxylic acid (0.168 g, 1.09 mmol) and thionyl chloride (4 mL) and allowed to stir at 79° C. for 2 h. The thionyl chloride was then removed by distillation. The crude acid chloride was cooled to 65° C., and then dissolved in THF (5 mL). 5-(4-Amino-benzyl)-1,3-dihydro-indol-2-one (0.200 g, 0.840 mmol) was added to the THF solution of the acid chloride, and the mixture was allowed to reflux overnight. Subsequently, the reaction mixture was allowed to cool to room temperature. The room temperature reaction mixture was concentrated in vacuo, and the crude residue was dissolved in EtOH (5 mL). The ethanolic solution was treated with 1M NaOH(aq) (2 mL) and stirred for 30 min. The basic solution was acidified to a pH of 1 with 1M HCl(aq) yielding a pale yellow precipitate. The pale yellow solids were filtered to afford the pure product (0.141 g, 0.377 mmol, 34.5%).

Provenance & Evidence