Potassium Permanganate → HCID 59425724, compound

Participants

Reaction Steps

1-Ethyl-3-formyl-1H-indole-6-carboxylic acid methyl ester (800 mg, 3.5 mmol), prepared as shown in example 1P, step A, was dissolved in acetone (98 mL). A solution of KMnO4 (655 mg, 4.15 mmol) in H2O (31 mL) was added. The reaction mixture was stirred at room temperature for 90 minutes. Another addition of KMnO4 (108 mg) in H2O (6 mL), followed by stirring for another 45 minutes was required to drive the reaction to completion. The reaction mixture was then quenched with 10% H2O2 (1.5 mL). The mixture was filtered through celite. The filtrate was stripped down under vacuum to roughly ⅓ of the volume. The residue was acidified with 6N HCl, and was extracted into ethyl acetate. The solids isolated from the ethyl acetate layer were triturated with acetone to yield 1-ethyl-1H-indole-3,6-dicarboxylic acid 6-methyl ester (696 mg, 79%) as a light orange solid.

Provenance & Evidence