反应详情

A suspension of 2-chloro-6-fluoro-3,5-dimethoxy-benzoic acid methyl ester (7.9 g, 31.9 mmol) and sodium hydroxide (3.2 g, 79.6 mmol) in 96 mL of anhydrous ethanol is refluxed for 24 hours. The ethanol is concentrated in vacuo and solid residue is dissolved in water and extracted twice with ether. The aqueous layer is acidified with Conc. HCl and a white precipitate is filtered, washed with cold water and dried in vacuo to afford 2-chloro-6-fluoro-3,5-dimethoxy-benzoic acid (21); 1H NMR 400 MHz (CDCl3) δ 6.61 (d, 1H), 3.87 (s, 3H), 3.84 (s, 3H); MS m/z 235.0 (M+1).

1. temperatureis refluxed for 24 hours
2. concentrationThe ethanol is concentrated in vacuo and solid residue
3. dissolutionis dissolved in water
4. extractionextracted twice with ether
5. filtrationa white precipitate is filtered
6. washwashed with cold water
7. customdried in vacuo