Methanol → 2-Amino-5-cyanobenzoic acid

Participants

Reaction Steps

Air was bubbled through a stirred solution of 5-cyano-3-methylthio-2-oxoindole (18.0 g, 88.1 mmol) and potassium hydroxide (5.9 g, 105.2 mmol) in a 9:1 mixture of methanol:water at room temperature for 5 hours. Further potassium hydroxide (5.9 g, 105.2 mmol) was added and the air bubbling continued overnight. The methanol was removed in vacuo, and the residue was carefully acidifed with 2N aq. HCl. The resulting precipitate was collected by filtration, and triturated with ethyl acetate to give 2-amino-5-cyanobenzoic acid as a pale brown solid (4.8 g, 29.6 mmol, 34%); δH [2H6]DMSO 8.02 (1H, d), 7.55 (1H, dd), 7.50 (2H, br s), 6.86 (1H, d).

Provenance & Evidence