反应详情

温度

5 °C

After continuously adding 1.68 g of diisopropylamine under a nitrogen atmosphere at 5° C. for 1 hour to a solution formed by adding 0.79 g of 2-propanol to 12.00 g of a hexane solution of (R)-2-bromoisovaleric acid obtained in Example 3 (containing 3.00 g of (R)-2-bromoisovaleric acid) to crystallize. They were successively stirred at 5° C. for 2 hours. The obtained crystals were filtered under a reduced pressure and then the crystals were washed with 3 ml of a mixed solution of hexane/2-propanol=15/1 (V/V) cooled to 5° C. The obtained crystals were dried under a reduced pressure to obtain 4.35 g of an (R)-2-bromoisovaleric acid diisopropyl amine salt (optical purity 99.1% ee, crystallization yield 93%, apparent purity 98.2%, impurity content 2-hydroxyisovaleric acid: not detected, bromine ingredient: 0.69%).

1. customformed
2. customto crystallize
3. filtrationThe obtained crystals were filtered under a reduced pressure
4. washthe crystals were washed with 3 ml of a mixed solution of hexane/2-propanol=15/1 (V/V)
5. temperaturecooled to 5° C
6. customThe obtained crystals were dried under a reduced pressure