Isopropanol → (r)-2-Bromoisovaleric acid diisopropylamine salt
Reaction equation
[CH:1]([NH:4][CH:5]([CH3:7])[CH3:6])([CH3:3])[CH3:2].CC(O)C.[Br:12][C@H:13]([CH:17]([CH3:19])[CH3:18])[C:14]([OH:16])=[O:15]>CCCCCC>[CH:1]([NH:4][CH:5]([CH3:7])[CH3:6])([CH3:3])[CH3:2].[Br:12][C@H:13]([CH:17]([CH3:19])[CH3:18])[C:14]([OH:16])=[O:15]Participants
Reactant 3
Product 1
Reagents, catalysts & solvents 1
Conditions
- Temperature
- 5 °C
Procedure
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%).
Workup
- customformed
- customto crystallize
- filtrationThe obtained crystals were filtered under a reduced pressure
- washthe crystals were washed with 3 ml of a mixed solution of hexane/2-propanol=15/1 (V/V)
- temperaturecooled to 5° C
- customThe obtained crystals were dried under a reduced pressure
Sources & evidence
- ORD record
- ord-90f4ff0f9dea41238f9451c45761c35b
- Source dataset
- uspto-grants-2009_01
- Patent number
- US07473803B2
Reaction notes
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