Methanol → 6-cyano-3-methyl-1-(1-methylethyl)-1H-indole-4-carboxylic acid

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Reaction Steps

To a 50 ml round bottom was added methyl 6-cyano-3-methyl-1-(1-methylethyl)-1H-indole-4-carboxylate (230 mg, 0.897 mmol), followed by methanol (1 mL) and THF (1 mL). To the solution was added 3 M NaOH (0.449 mL, 2.69 mmol). The reaction stirred at rt for 20 h. The reaction was evaporated and treated with acidic water to pH 5. A brown solid crashed out and was collected by filtration. The solid was an impurity. The pH of the liquid was adjusted to 3 and the liquid was evaporated leaving a residue. Trituration of the residue with water, followed by filtration yielded 6-cyano-3-methyl-1-(1-methylethyl)-1H-indole-4-carboxylic acid (155 mg, 0.576 mmol, 64.2% yield) as a yellow solid. 1H NMR (400 MHz, DMSO-δ6) δ ppm 13.16 (br. s., 1H) 8.33 (s, 1H) 7.78 (s, 1H) 7.66 (s, 1H) 4.81-4.98 (m, 1H) 2.33 (s, 4H) 1.45 (d, J=6.57 Hz, 6H). MS(ES) [M+H]+ 243.3.

Provenance & Evidence