反应详情

The NHS (N-hydroxy succinimide) ester of bromoacetic acid was prepared as follows: 100 mmoles of (13.9 g) of bromoacetic acid were dissolved in 50 ml of anhydrous DMF, to this solution 100 mmoles (20.6 g) of N—N-Dicyclohexylcarbodiimide were added with stirring followed by 100 mmoles of N-hydroxysuccinimide (11.9 g adjusted for 100% purity), and the mixture was stirred for 6 hours at 37° C. The mixture was then placed for 2 hours at −20° C. to accelerate the precipitation of hydroxyurea, which was removed by filtration. In the filtrate the DMF was removed under reduced pressure at 45° C. and the active ester was recrystallized from 2-propanal.

1. additionwere added
2. stirringthe mixture was stirred for 6 hours at 37° C
3. customthe precipitation of hydroxyurea, which
4. customwas removed by filtration
5. customIn the filtrate the DMF was removed under reduced pressure at 45° C.
6. customthe active ester was recrystallized from 2-propanal