反应详情

To a cooled solution (−70° C.) of 3-bromo-4-chloro-N-(2-methoxy-phenyl)-N-methyl-benzamide (2 g, 5.64 mmol) in DCM (20 mL), BBr3 (1.7 mL, 18 mmol) was added drop-wise over a 20 minute period. The reaction temperature was allowed to increase to room temperature over 12 hrs until completion of the reaction. After concentration in vacuo the mixture was partitioned between DCM and water. 1N NaOH was added to increase pH to −5. The organic layer was separated and washed with brine and dried over Na2SO4. Concentration and purification by silica gel column chromatography eluting with hexane/ethyl acetate (4/1 with gradient up to 3/2) yielded 3-bromo-4-chloro-N-(2-hydroxy-phenyl)-N-methyl-benzamide (1.78 g, 93%). MS [M+H]+: 341.9; tR=2.56 min. (method 1)

1. concentrationAfter concentration in vacuo the mixture
2. customwas partitioned between DCM and water
3. addition1N NaOH was added
4. temperatureto increase pH to −5
5. customThe organic layer was separated
6. washwashed with brine
7. dry with materialdried over Na2SO4
8. concentrationConcentration and purification by silica gel column chromatography
9. washeluting with hexane/ethyl acetate (4/1 with gradient up to 3/2)