Water → 2-Benzylpiperazine

HRID 456508Notes

Reaction equation

HRID 456508 reaction equation
[CH2:1]([CH:8]1[NH:13][C:12](=O)[CH2:11][NH:10][C:9]1=O)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.[H-].[Al+3].[Li+].[H-].[H-].[H-].O>C(OCC)C>[CH2:1]([CH:8]1[NH:13][CH2:12][CH2:11][NH:10][CH2:9]1)[C:2]1[CH:3]=[CH:4][CH:5]=[CH:6][CH:7]=1

Participants

5

Reactant 3

HCID 962WaterHCID 1384093-Benzyl-3,6-dihydropyrazine-2,5-diolHCID 21226445Aluminium lithium hydride

Product 1

HCID 5590332-Benzylpiperazine

Reagents, catalysts & solvents 1

HCID 3283Diethyl EtherSolvent2×

Conditions

Temperature
0 °C

Procedure

To a suspension of 3-benzyl-piperazine-2,5-dione (14.98 g, 73 mmol, prepared following generally the procedure of Halpern and Westley, J. Org. Chem. 1968, 33, 864) in dry diethyl ether (500 mL) is added dropwise to a solution of lithium aluminum hydride (400 mL of a 1 M solution in diethyl ether, 400 mmol, 5.4 eq). The suspension is heated at reflux for 23 hours and then cooled to 0° C. Water (70 mL) is then cautiously added and the resulting suspension is warmed to room temperature. After 3 hours the suspension is filtered and the solid washed with diethyl ether (1 L). The filtrate is concentrated under vacuum to provide crude title compound (11.40 g, 88%) as a yellow, crystalline solid. A sample (2 g) is recrystallized from cyclohexane and then from toluene to provide the purified title compound (0.83 g) as a fine, white crystals: mp 80–81° C.

Workup

  1. customprepared
  2. temperatureThe suspension is heated
  3. temperatureat reflux for 23 hours
  4. temperaturethe resulting suspension is warmed to room temperature
  5. filtrationAfter 3 hours the suspension is filtered
  6. washthe solid washed with diethyl ether (1 L)
  7. concentrationThe filtrate is concentrated under vacuum
  8. customto provide crude title compound (11.40 g, 88%) as a yellow, crystalline solid
  9. customA sample (2 g) is recrystallized from cyclohexane
  10. customfrom toluene to provide the
  11. custompurified title compound (0.83 g) as a fine, white crystals

Sources & evidence

ORD record
ord-84571cc5b1b54d4aa238e67f2fc8b6f0
Source dataset
uspto-grants-2007_03
Patent number
US07186724B2

Reaction notes

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