1-Chloro-4-(chloromethyl)benzene → 3-[(4-Chlorophenyl)methyl]-2-pyrrolidinone

Temperature

-76 °C

In a flask was added diisopropylamine (3.22 g, 31.8 mmole) and dry THF (60 ml). The content of the flask was kept under nitrogen, and was then cooled to −76° C. To the cool solution was dropwise added n-butyllithium (n-BuLi, 32 mmole, 20 ml, 1.6 M in hexane). After completed addition, the solution was stirred for 10 minutes, and a solution of 1-Trimethylsilanyl-pyrrolidin-2-one (5.00 g, 31.8 mmole, prepared according to literature methods) in dry THF (5 ml) was added dropwise. The solution was then stirred for an additional 20 minutes and a solution of 4-Chlorobenzyl chloride (5.13 g, 32 mmole) in THF (5 ml) was added via a syringe during 5 minutes. The resulting mixture was stirred at −76° C. for 1 hour, and was then allowed to reach the ambient temperature and was stirred over night. Water (40 ml) was added and the mixture was stirred vigorously for 60 minutes. The phases were separated and the organic phase was washed with brine, and was finally evaporated, giving an oil which crystallized on standing. The solid was triturated with heptane:EtOAc 2:1 and was filtered, giving a partly purified solid. The solid was purified on silica (DCM to DCM: MeOH 99:1 to 98:2 to 97:3 gradient) giving 1.3 g (20%) of the sub-title compound.

1. additionaddition
2. stirringThe solution was then stirred for an additional 20 minutes
3. stirringThe resulting mixture was stirred at −76° C. for 1 hour
4. customthe ambient temperature
5. stirringwas stirred over night
6. stirringthe mixture was stirred vigorously for 60 minutes
7. customThe phases were separated
8. washthe organic phase was washed with brine
9. customwas finally evaporated
10. customgiving an oil which
11. customcrystallized
12. customThe solid was triturated with heptane:EtOAc 2:1
13. filtrationwas filtered
14. customgiving a partly purified solid
15. customThe solid was purified on silica (DCM to DCM: MeOH 99:1 to 98:2 to 97:3 gradient)

ORD record

ord-70c9776517aa4c38af74b4a56fa4fe34

Source dataset

uspto-grants-2005_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06943188B2