Dicyclohexylamine → (r)-2-Bromoisovaleric acid dicyclohexylamine salt

HRID 1452816Notes

Reaction equation

[Br:1][C@H:2]([CH:6]([CH3:8])[CH3:7])[C:3]([OH:5])=[O:4].[CH:9]1([NH:15][CH:16]2[CH2:21][CH2:20][CH2:19][CH2:18][CH2:17]2)[CH2:14][CH2:13][CH2:12][CH2:11][CH2:10]1>CCCCCC>[CH:16]1([NH:15][CH:9]2[CH2:10][CH2:11][CH2:12][CH2:13][CH2:14]2)[CH2:17][CH2:18][CH2:19][CH2:20][CH2:21]1.[Br:1][C@H:2]([CH:6]([CH3:8])[CH3:7])[C:3]([OH:5])=[O:4]

Participants

Conditions

Temperature: 5 °C

Procedure

To 325.2 g of a hexane solution of (R)-2-bromoisovaleric acid obtained in Example 4 (containing 75.0 g of (R)-2-bromoisovaleric acid), 530.9 g of hexane and 269.7 g of2-propanol were further added. Seed crystals were added when about ⅔ for 72.5 g of dicyclohexylamine was added continuously for 1.0 hour under a nitrogen atmosphere at 5° C. to crystallize. Further, after continuously adding the remaining about ⅓ for dicyclohexylamine at 5° C. for 0.5 hours, they were stirred at 5° C. for 1 hour. The obtained crystals were filtered under a reduced pressure and then the crystals were washed for 3 times with 150 ml of hexane. The obtained wet crystals were dried under a reduced pressure to obtain 126.45 g of a (R)-2-bromoisovaleric acid dicyclohexylamine salt (optical purity 98.0% ee, crystallization yield 87%, apparent purity 98.9%, impurity content 2-hydroxy isovaleric acid: not detected, bromine content: 0.64%).

Workup

additionwas added continuously for 1.0 hour under a nitrogen atmosphere at 5° C.
customto crystallize
additionFurther, after continuously adding the remaining about ⅓ for dicyclohexylamine at 5° C. for 0.5 hours
filtrationThe obtained crystals were filtered under a reduced pressure
washthe crystals were washed for 3 times with 150 ml of hexane
customThe obtained wet crystals were dried under a reduced pressure

Sources & evidence

ORD record: ord-8aabeecc75714453ac8bef67fa28756f
Source dataset: uspto-grants-2009_01
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07473803B2

Reaction notes

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