1-Bromopropane → 1-Propyl-1H-indole-2,5-dicarboxylic acid

Participants

Reaction Steps

Sodium hydride (60% suspension, 125 mg, 5 mmol) was added to a stirred solution of 1H-indole-2,5-dicarboxylic acid (525 mg, 2 mmol) in dry DMF (10 mL) and maintained at ambient temperature for 1 hour. The reaction was cooled to 0° C. and then propyl bromide (0.275 mL, 3 mmol) was added. After 3 days the reaction was quenched by addition of 5% aqueous NH4Cl. The mixture was concentrated to dryness and then purified on a silica gel column using 5% EtOAc/toluene. The product was then dissolved in 30 mL ethanol and 10 mL of 2 M NaOH was added. The solution was heated at 55° C. for 2 days. The ethanol was removed in vacuo and the resulting aqueous solution was acidified with 0.01 M HCl to pH 3. The resulting precipitate was filtered and rinsed twice with water. The isolated product was dried by evaporation from absolute ethanol (3×) to give 340 mg (67%) of 87.

Provenance & Evidence