反应详情

温度

0 °C

Methanesulfonic acid (140 ml) was added dropwise, under ice cooling, to a solution consisting of 4-tert-butyl-5-hydroxybenzofuran [J. Org. Chem., 53, 4135 (1988); 35 g, 0.18 mol], tert-butyl alcohol (70 g, 0.84 mol) and chloroform (50 ml). After stirring at 0° C. for 20 min, the mixture was poured into ice water. Subsequently, the mixture was neutralized with an aqueous solution of 1N sodium hydroxide and subjected to extraction with ethyl acetate. The extracted layer was washed with a saturated aqueous solution of sodium hydrogen carbonate, dried over anhydrous magnesium sulfate, and concentrated. The concentrate was purified by silica gel chromatography (n-hexane) to afford 2,4,6-tri-tert-butyl-5-hydroxybenzofuran [10.87 g (yield, 20%)]. Also obtained, though in low yield, was 4,6-di-tert-butyl-5-hydroxybenzofuran.

1. extractionsubjected to extraction with ethyl acetate
2. washThe extracted layer was washed with a saturated aqueous solution of sodium hydrogen carbonate
3. dry with materialdried over anhydrous magnesium sulfate
4. concentrationconcentrated
5. customThe concentrate was purified by silica gel chromatography (n-hexane)