Phenethyl bromide → 4-Phenethylpiperazin-2-one

Temperature

80 °C

A suspension of (2-bromoethyl)benzene (4.10 mL, 30.0 mmol), piperazin-2-one (3.00 g, 30.0 mmol) and K2CO3 (4.90 g, 36.0 mmol) in DMSO (60.0 mL) was stirred at 80° C. for 5 h. The reaction mixture was cooled to room temperature and filtered. The filtrate was then washed with water (200 mL) and extracted with methylene chloride (2×). The combined organic layers were washed with brine, dried over MgSO4, filtered, and concentrated. The result yellow solid was then dissolved in 1 N HCl (120 mL) and washed with methylene chloride. The aqueous layer was separated, basified with 6 N NaOH, and extracted with methylene chloride (3×). The combined organic layers were dried over MgSO4, filtered, and concentrated. The residue was titrated with hexanes and filtered. The filtered solid was dried under reduced pressure to give the title compound (4.50 g, 74%) as an off-white solid: 1H NMR (500 MHz, CDCl3) δ 7.31-7.28 (m, 2H), 7.23-7.19 (m, 3H), 6.17 (br s, 1H), 3.40-3.37 (m, 2H), 3.23 (s, 2H), 2.83-2.79 (m, 2H), 2.73-2.67 (m, 4H).

1. temperatureThe reaction mixture was cooled to room temperature
2. filtrationfiltered
3. washThe filtrate was then washed with water (200 mL)
4. extractionextracted with methylene chloride (2×)
5. washThe combined organic layers were washed with brine
6. dry with materialdried over MgSO4
7. filtrationfiltered
8. concentrationconcentrated
9. dissolutionThe result yellow solid was then dissolved in 1 N HCl (120 mL)
10. washwashed with methylene chloride
11. customThe aqueous layer was separated
12. extractionextracted with methylene chloride (3×)
13. dry with materialThe combined organic layers were dried over MgSO4
14. filtrationfiltered
15. concentrationconcentrated
16. filtrationfiltered
17. customThe filtered solid was dried under reduced pressure

ORD record

ord-1f3db50177a243538d914ffb9d8c62b9

Source dataset

uspto-grants-2015_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08993765B2