反应详情

A solution of 2,5-dibromoxylene (8.0 g, 30.3 mmol) in diethyl ether (120 mL) is cooled to −78° C. and then treated with n-buthyllithium (20 mL, 1.6 M in hexane). After stirring for 40 min, DMF (6 mL) is slowly added. The mixture is warmed to rt and stirred for 1 h. The mixture is cooled again to −78° C. before another portion of n-butyllithium (5 mL) is added. The reaction mixture is allowed to warm to rt and stirred for another hour. The reaction is quenched by adding 5% aq. HCl. The mixture is extracted with EA, and the extract is concentrated in vacuo. The crude product is purified by CC on silica gel eluting with heptane:EA 5:1 to give 4-bromo-3,5-dimethyl-benzaldehyde (8.2 g) as a white soft solid.

1. stirringstirred for 1 h
2. additionis added
3. temperatureto warm to rt
4. stirringstirred for another hour
5. customThe reaction is quenched
6. additionby adding 5% aq. HCl
7. extractionThe mixture is extracted with EA
8. concentrationthe extract is concentrated in vacuo
9. customThe crude product is purified by CC on silica gel eluting with heptane:EA 5:1