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, 1 M 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-4fedc7f120e9434183e4b2c184b0750d

Source dataset

uspto-grants-2009_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07582761B2