Diisopropylamine → (r)-2-Bromoisovaleric acid diisopropylamine salt

Temperature

0 °C

After continuously adding 16 ml of diisopropylamine to 128.9 g of a methyl t-butyl ether solution of (R)-2-bromoisovaleric acid obtained in Comparative Example 2 was continuously added at −4° C. for 12 min to crystallize, they were stirred successively at 0° C. for 1 hour. Obtained crystals were filtered under a reduced pressure, and then washed with 30 ml of methyl t-butyl ether. Obtained crystals were dried under a reduced pressure to obtain 27.81 g of (R)-2-bromoisovaleric acid diisopropylamine salt (optical purity 98.1% ee, crystallization yield 80%, apparent purity 92.5%, impurity content 2-hydroxy isovaleric acid; 0.31%, bromine content: 4.58%).

1. customobtained in Comparative Example 2
2. additionwas continuously added at −4° C. for 12 min
3. customto crystallize
4. customObtained crystals
5. filtrationwere filtered under a reduced pressure
6. washwashed with 30 ml of methyl t-butyl ether
7. customObtained crystals
8. customwere dried under a reduced pressure

ORD record

ord-ea1d59226c5b4bf5879c338f21fd1cce

Source dataset

uspto-grants-2009_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07473803B2