反应详情

To a solution of 526 mg (1.69 mmol) of 2-amino-3-chloro-5-iodo-benzoic acid methyl ester in 9.0 mL methanol was added 474 mg of potassium hydroxide (8.44 mmol). The solution was stirred at room temperature for 18 hours. An additional 474 mg (8.44 mmol) of potassium hydroxide was added and the solution was heated in an oil bath at 45° C. for 4.5 hours. The solution was acidified to pH=3 by a dropwise addition of 1N aqueous hydrochloric acid. The resulting precipitate was collected by vacuum filtration. The solid was dissolved in methanol and concentrated to dryness. Acetone was added to the residue and the insoluble white precipitates were filtered off. The filtrate was concentrated to afford 500 mg (1.68 mmol, quantitative yield) of 2-amino-3-chloro-5-iodo-benzoic acid as a brown powder. 1H NMR (500 MHz, DMSO-d6) δ 7.95 (d, 1H), 7.76 (d, 1H), 6.91 (s, br., 2H); MS: m/z 295.8 (M−H+).

1. temperaturethe solution was heated in an oil bath at 45° C. for 4.5 hours
2. filtrationThe resulting precipitate was collected by vacuum filtration
3. dissolutionThe solid was dissolved in methanol
4. concentrationconcentrated to dryness
5. additionAcetone was added to the residue
6. customthe insoluble white precipitates
7. filtrationwere filtered off
8. concentrationThe filtrate was concentrated