Benzyl Bromide → (R)-1-Benzyl-3-methylpiperazine

Temperature

0 °C

To a solution of (R)-2-methylpiperazine (10 g, 100 mmol) in ethanol at room temperature was added K2CO3 (27.6 g, 200 mmol). The reaction mixture was cooled to 0° C., benzyl bromide (15.3 g, 89.5 mmol) was added and the reaction mixture was heated to 60° C. and stirred for 8 h. The reaction mixture was allowed to cool to room temperature, filtered through a filtration funnel and the filtrate was concentrated under reduced pressure to remove ethanol. The residue was washed with water and extracted with dichloromethane. The organic layer was dried over anhydrous sodium sulfate and concentrated under reduced pressure to afford crude product. The crude product was purified by silica gel (100-200 mesh) column chromatography eluting with 5% methanol in chloroform to afford pure 12.0 g of (R)-1-benzyl-3-methylpiperazine.

1. temperaturethe reaction mixture was heated to 60° C.
2. temperatureto cool to room temperature
3. filtrationfiltered through a filtration funnel
4. concentrationthe filtrate was concentrated under reduced pressure
5. customto remove ethanol
6. washThe residue was washed with water
7. extractionextracted with dichloromethane
8. dry with materialThe organic layer was dried over anhydrous sodium sulfate
9. concentrationconcentrated under reduced pressure
10. customto afford crude product
11. customThe crude product was purified by silica gel (100-200 mesh) column chromatography
12. washeluting with 5% methanol in chloroform

ORD record

ord-7ff1d6fa8eae4498820fccaedc44653f

Source dataset

uspto-grants-2012_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08258306B2