反应详情

8.16 g of 2,5-dimethylbenzothiazole was dissolved in 50 ml of carbon tetrachloride. To the solution were added 8.9 g of N-bromosuccinimide and 82 mg of benzoyl peroxide. The mixture was refluxed for 3 hours. The resulting insolubles were removed by filtration. The solvent of the filtrate was removed by distillation under reduced pressure to obtain 5-bromomethyl-2-methylbenzothiazole. It was suspended in 100 ml of 50% acetic acid. To the suspension was added 14.00 g of hexamethylenetetramine, and the mixture was refluxed for 1 hour. The reaction mixture was mixed with 200 ml of water. The resulting mixture was extracted with ethyl acetate. The extract was washed with a saturated aqueous sodium hydrogencarbonate solution, water and a saturated aqueous sodium chloride solution in this order, and dried over anhydrous magnesium sulfate. The solvent was removed by distillation under reduced pressure. The residue was purified by a column chromatography (eluant: n-hexane/ethyl acetate=3/1) to obtain 3.54 g of colorless crystals of 2-methyl-5-formylbenzothiazole having a melting point of 92°-94° C.

1. temperatureThe mixture was refluxed for 3 hours
2. customThe resulting insolubles were removed by filtration
3. customThe solvent of the filtrate was removed by distillation under reduced pressure