反应详情

To a THF (50 ml) solution of 2-bromo-5-methoxybenzaldehyde (10 g) was added dropwise a THF (30 ml) solution of the Grignard reagent prepared from 5-Bromo-1,3-benzodioxole (11.2 g) and Mg (1.6 g). The mixture was stirred for 1 hour at room temperature and ammonium chloride solution was added therein, then extracted with ethyl acetate. The extract was washed with water and dried with magnesium sulfate, then concentrated. The residue was purified with silica gel column (Hex/EA=3/1) to give (2-bromo-5-methoxyphenyl) (1,3-benzodioxol-5-yl)methanol as an oily substance (15 g). (2-bromo-5-methoxyphenyl)(1,3-benzodioxol-5-yl)methanol was dissolved in ether (300 ml) and n-BuLi(1.6M/Hex: 64 ml) was added dropwise at -78° C. The reaction mixture was stirred for 5 minutes at -78° C., then stirred for 1 hour at 0° C. To the mixture was added DMF (30 ml) and stirred for 1 hour at room temperature. To the reaction mixture was added water and extracted with ether. The extract was washed with water and dried with magnesium sulfate then concentrated under reduced pressure. The obtained residue was dissolved in toluene (250 ml) and maleimide (6 g) and p-toluenesulfonic acid monohydrate (1.0 g) were added thereto. The reaction mixture was refluxed for 20 hours and the separated solid was filtered off. The filtrate was concentrated under reduced pressure. To the obtained residue was added concentrated hydrochloric acid and heated under reflux for 1 hour. The mixture was cooled to room temperature and the resultant yellow-brown solid was collected by suction and washed with water, then recrystalized with THF to give the entitled compound (5.4 g).

1. extractionextracted with ethyl acetate
2. washThe extract was washed with water
3. dry with materialdried with magnesium sulfate
4. concentrationconcentrated
5. customThe residue was purified with silica gel column (Hex/EA=3/1)