反应详情

At 0° C., 10 g (48 mmol) of 3-(2-methyl-6-methylthiophenyl)-4,5-dihydroisoxazole are added a little at a time to 120 ml of conc. sulfuric acid, and the mixture is stirred for approximately 30 minutes. 3.7 g (23 mmol) of bromine are then added dropwise, and the mixture is stirred at 0° C. for 2.5 hours. Over a period of approximately 45 minutes, the mixture is subsequently allowed to warm to room temperature. A homogeneous solution forms. For work-up, the reaction mixture is poured into ice-water and extracted three times with methylene chloride. The organic phase is washed with sodium bicarbonate solution, dried with magnesium sulfate and concentrated. This gives 11.4 g of crude product which is employed in the next step without any further purification.

1. stirringthe mixture is stirred at 0° C. for 2.5 hours
2. waitOver a period of approximately 45 minutes
3. extractionextracted three times with methylene chloride
4. washThe organic phase is washed with sodium bicarbonate solution
5. dry with materialdried with magnesium sulfate
6. concentrationconcentrated
7. customThis gives 11.4 g of crude product which is employed in the next step without any further purification