反应详情

According to the method of Heterocycles, 16, 2091 (1981), combine 2-methoxy-5-trifluoromethoxybenzaldehyde (0.58 g, 2.65 mmol) and 2-methylbut-2-ene (37 mL) in t-butanol (16 mL). Add dropwise a solution of sodium dihydrogen phosphate hydrate (0.92 g) and sodium chlorite (0.42 g, 4.7 mmol) in water (10 mL). After 4 hours, adjust the pH of the reaction mixture to about 8 to 9 using a 1M aqueous sodium hydroxide solution. Evaporate the reaction mixture in vacuo at about ambient temperature to remove most of the t-butanol. Add water (40 mL) and extract three times with hexane (10 mL). Adjust the pH of the aqueous layer to about 1 using a 1M aqueous hydrochloric acid solution and extract five times with diethyl ether. Combine the organic layers, dry over Na2SO4, filter, and evaporate in vacuo to give a residue. Chromatograph the residue on silica gel eluting with 1/1 ethyl acetate/hexane containing 0.5% acetic acid to give 2-methoxy-5-trifluoromethoxybenzoic acid: Rf =0.34 (silica gel, 1/1 ethyl acetate/hexane containing 0.5% acetic acid).

1. customEvaporate the reaction mixture in vacuo at about ambient temperature
2. customto remove most of the t-butanol
3. extractionAdd water (40 mL) and extract three times with hexane (10 mL)
4. extractionextract five times with diethyl ether
5. dry with materialdry over Na2SO4
6. filtrationfilter
7. customevaporate in vacuo
8. customto give a residue