反应详情

温度

0 °C

To a solution of (3-chloro-phenyl) acetic acid methyl ester (5.0 g, 27.1 mmol, commercially available) in concentrated sulfuric acid (7.5 mL, 140.7 mmol) at 0° C. was added drop-wise nitric acid (2.52 g, 70%, 28.0 mmol). After stirring at 0° C. for two hrs, the reaction mixture was poured into ice water and was extracted into dichloromethane. The organic extract was washed with brine, dried (anhydrous sodium sulfate), filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography over silica gel eluting with 6% ethyl acetate in hexane to give the desired (3-chloro-4-nitro-phenyl)acetic acid methyl ester as an oil (2.1 g, 33%), and (5-chloro-2-nitro-phenyl)acetic acid methyl ester as an oil (3.2 g, 51%). 1H NMR (CDCl3) δ:3.69 (s, 2H), 3.74(s, 3H), 7.33 (dd, 1H, J=8.4 Hz, 1.9 Hz), 7.50 (d, 1H, 3=1.8 Hz), 7.87 (d, 1H, 3=8.4 Hz.

1. extractionwas extracted into dichloromethane
2. extractionThe organic extract
3. washwas washed with brine
4. dry with materialdried (anhydrous sodium sulfate)
5. filtrationfiltered
6. concentrationconcentrated under reduced pressure
7. customThe residue was purified by flash column chromatography over silica gel eluting with 6% ethyl acetate in hexane