Hydrochloric Acid → 3-Amino-2,6-dichlorobenzoic acid

Temperature

60 °C

2,6-Dichloro-3-nitro-benzoic acid (10 g, 42 mmol, Step a) was added to concentrated hydrochloric acid (100 mL), followed by stannous chloride dihydrate (38 g, 169 mmol). The reaction mixture was heated at 60° C. for 1 hour. The reaction mixture was diluted with water (500 mL) and extracted with ethyl acetate (2×300 mL). The combined organic layer was dried over anhydrous sodium sulfate and concentrated under vacuum to afford the crude product (sticky material). The crude material was dissolved in water (200 mL, turbid solution) and treated slowly with aqueous sodium hydroxide (20%) solution till precipitation while maintaining the pH 1-2 (dense precipitate was observed). The precipitate was filtered and filtrate was extracted with ethyl acetate (2×200 mL) and dried over anhydrous sodium sulfate and concentrated under vacuum to yield 3-amino-2,6-dichloro-benzoic acid as a creamish solid (6 gm, 69%).

1. extractionextracted with ethyl acetate (2×300 mL)
2. dry with materialThe combined organic layer was dried over anhydrous sodium sulfate
3. concentrationconcentrated under vacuum
4. customto afford the crude product (sticky material)
5. temperaturewhile maintaining the pH 1-2 (dense precipitate was observed)
6. filtrationThe precipitate was filtered
7. extractionfiltrate was extracted with ethyl acetate (2×200 mL)
8. dry with materialdried over anhydrous sodium sulfate
9. concentrationconcentrated under vacuum

ORD record

ord-0f2ad58b26dc4907ba943f0fb9c9f9ff

Source dataset

uspto-grants-2015_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08980911B2