反应详情

温度

70 °C

A solution of (3,5-dimethyl-4-hydroxy-phenyl)-acetic acid (5a) (12.4 g, 0.069 mmol) in methanol (300 mL) was treated with concentrated sulfuric acid (6.25 mL). The resulting solution was heated to 70° C. overnight. At this time, the reaction was cooled to room temperature. The reaction was concentrated under vacuum. The residue was diluted with ethyl acetate (700 mL) and was washed with water (2×250 mL). The organics were dried over magnesium sulfate, filtered and concentrated under vacuum to give an orange solid. The solid was slurried in 10% ethyl acetate/petroleum ether and was stirred for 1 h. The solid was collected by filtration, washed with 10% ethyl acetate/petroleum ether, and dried under vacuum overnight. The residue was purified by column chromatography using silica gel eluted with 10-15% ethyl acetate in petroleum ether to afford (3,5-dimethyl-4-hydroxy-phenyl)-acetic acid methyl ester (6a) (1.93 g, 86%) as an off-white solid; EI(+)-HRMS m/z calcd for C11H14O3 (M+) 194.0943, found 191.0942. Molecular Weight=194.2324; Exact Mass=194.0943

1. temperatureAt this time, the reaction was cooled to room temperature
2. concentrationThe reaction was concentrated under vacuum
3. additionThe residue was diluted with ethyl acetate (700 mL)
4. washwas washed with water (2×250 mL)
5. dry with materialThe organics were dried over magnesium sulfate
6. filtrationfiltered
7. concentrationconcentrated under vacuum
8. customto give an orange solid
9. filtrationThe solid was collected by filtration
10. washwashed with 10% ethyl acetate/petroleum ether
11. customdried under vacuum overnight
12. customThe residue was purified by column chromatography
13. washeluted with 10-15% ethyl acetate in petroleum ether