反应详情

温度

70 °C

step 1—To a suspension of 4-tert-butyl-3-methoxybenzoic acid (3.00 g, 14.4 mmol, CASRN 79822-46-1) in H2O (30 mL) was added solid NaOH (1.21 g, 30.2 mmol). NBS (2.81 g, 15.8 mmol) was added in several portions over 10 min. The reaction mixture was stirred at RT for 1 h before additional NaOH (0.12 g, 3.0 mmol) and NBS (0.28 g, 1.6 mmol) were added. After stirring for an additional 1 h, the reaction mixture was acidified with 48% HBr, diluted with H2O then thrice extracted with Et2O. The combined extracts were washed sequentially with 10% aqueous Na2S2O3 and H2O, dried (MgSO4), filtered and concentrated under reduced pressure to afford a pale yellow solid which was dissolved in MeOH (50 mL) and con H2SO4 (5 mL) was slowly added. The reaction mixture was heated at 70° C. for 3 h, cooled to RT overnight then concentrated under reduced pressure. The residue was diluted with H2O and thrice extracted with Et2O. The combined extracts were washed with sequentially 1.0 M aq NaOH and H2O, dried (MgSO4), filtered and concentrated under reduced pressure to afford 3.7 g (85%) of 2-bromo-4-tert-butyl-5-methoxybenzoic acid methyl ester (64, CASRN 911115-95-2)

1. additionwere added
2. extractionthrice extracted with Et2O
3. washThe combined extracts were washed sequentially with 10% aqueous Na2S2O3 and H2O
4. dry with materialdried (MgSO4)
5. filtrationfiltered
6. concentrationconcentrated under reduced pressure
7. customto afford a pale yellow solid which
8. temperaturecooled to RT overnight
9. concentrationthen concentrated under reduced pressure
10. additionThe residue was diluted with H2O and thrice
11. extractionextracted with Et2O
12. washThe combined extracts were washed with sequentially 1.0 M aq NaOH and H2O
13. dry with materialdried (MgSO4)
14. filtrationfiltered
15. concentrationconcentrated under reduced pressure