反应详情

温度

-78 °C

In 300 ml of dry tetrahydrofuran, was dissolved 32.0 g of 6-bromo-5-methyl-1,4-benzodioxane and after cooling the solution to -78° C., 96.7 ml of n-butyl lithium (n-hexane solution) was added dropwise over 20 minutes or more. After stirring at the same temperature for 1.5 hours, the reaction mixture was poured onto crushed dry ice and dry ice was sublimated while stirring. Water was added to the mixture and the tetrahydrofuran was removed under reduced pressure. The resulting alkaline aqueous solution was washed with methylene chloride and adjusted to pH 3 with a 5% hydrochloric acid, and the precipitated crystals were collected by filtration and dried to obtain 20.9 g of 5-methyl-1, 4-benzodioxan-6-carboxylic acid (yield: 77%).

1. additionthe reaction mixture was poured
2. stirringwhile stirring
3. customthe tetrahydrofuran was removed under reduced pressure
4. washThe resulting alkaline aqueous solution was washed with methylene chloride
5. filtrationthe precipitated crystals were collected by filtration
6. customdried