Aluminium lithium hydride → (2R)-2-butylpiperazine

To a cooled to −78° C. solution of (3R)-3-butyl-2,5-piperazinedione from step (b) above (600 mg, 2.52 mmol) in THF (10 mL) was added dropwise lithium aluminum hydride (21 mL, 21.1 mmol, 1M in THF, Aldrich). The mixture was stirred at room temperature for 1 h, and then heated at reflux for 16 h. The mixture was cooled to 0° C. and quenched with sodium sulfate decahydrate until the gas evolution ceased. The mixture was stirred at room temperature for 3 h, filtered and the filter cake was washed with THF (2×10 mL). The filtrate was concentrated in vacuo to give the title compound as a yellow solid. MS (ESI, positive ion) m/z: 143 (M+1).

1. temperatureheated
2. temperatureat reflux for 16 h
3. temperatureThe mixture was cooled to 0° C.
4. customquenched with sodium sulfate decahydrate until the gas evolution
5. stirringThe mixture was stirred at room temperature for 3 h
6. filtrationfiltered
7. washthe filter cake was washed with THF (2×10 mL)
8. concentrationThe filtrate was concentrated in vacuo

ORD record

ord-9704b4f9e3544f94acef2f24db91defb

Source dataset

uspto-grants-2011_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08026241B2