反应详情

Under nitrogen atmosphere, to a solution of 4-bromo-3,5-dimethoxybenzyl ethyl ether (440.0 g) in tetrahydrofuran (4.0 L) was added dropwise n-butyl lithium (1.6 M n-hexane solution, 1.1 L) at −60° C. After stirring for 15 minutes at the same temperature, trimethyl borate (249.3 g) was added. The temperature of the mixture was gradually elevated, followed by stirring for 1 hour under ice-cooling. To the mixture was added dropwise 10% aqueous sulfuric acid solution (835 g). The mixture was extracted with ethyl acetate and the organic layer was washed with water and saturated aqueous NaCl solution. After drying over magnesium sulfate, the solvent was removed in vacuo. The residue was dissolved in isopropyl ether with heating and cooled. The crystalline precipitates were collected by filtration and dried to yield 4-ethyoxymethyl-2,6-dimetoxyphenylboronic acid (312.9 g).

1. additionwas added
2. temperaturecooling
3. extractionThe mixture was extracted with ethyl acetate
4. washthe organic layer was washed with water and saturated aqueous NaCl solution
5. dry with materialAfter drying over magnesium sulfate
6. customthe solvent was removed in vacuo
7. dissolutionThe residue was dissolved in isopropyl ether
8. temperaturewith heating
9. temperaturecooled
10. customThe crystalline precipitates
11. filtrationwere collected by filtration
12. customdried