反应详情

To a solution of 3,4-dimethylphenol (2.48 g, 20.3 mmol, 1 equiv) in DCM (200 mL) at −78° C. (IPA/dry ice) was added dropwise bromine (1.05 mL, 20.3 mmol, 1 equiv). After 1 h, 1 N Na2SO3 was added and the cold bath was removed. After warming to ambient temperature, the DCM layer was separated, dried (Na2SO4), and concentrated in vacuo to provide the product (4.09 g, 100%) as a yellow solid. Regioselectivity>10:1, use as is. 1H NMR (400 MHz, CDCl3) δ 7.21 (s, 1H), 6.83 (s, 1H), 5.26 (s, 1H), 2.20 (s, 3H), 2.18 (s, 3H).

1. customthe cold bath was removed
2. customthe DCM layer was separated
3. dry with materialdried (Na2SO4)
4. concentrationconcentrated in vacuo