Triethylamine → Ethyl 1,4-dibenzylpiperazine-2-carboxylate

HRID 2396482Notes

Reaction equation

HRID 2396482 reaction equation
Br[CH:2]([CH2:8]Br)[C:3]([O:5][CH2:6][CH3:7])=[O:4].[CH2:10]([NH:17][CH2:18][CH2:19][NH:20][CH2:21][C:22]1[CH:27]=[CH:26][CH:25]=[CH:24][CH:23]=1)[C:11]1[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=1.C(N(CC)CC)C.Br.C(N(CC)CC)C>C1C=CC=CC=1>[CH2:10]([N:17]1[CH2:18][CH2:19][N:20]([CH2:21][C:22]2[CH:27]=[CH:26][CH:25]=[CH:24][CH:23]=2)[CH2:8][CH:2]1[C:3]([O:5][CH2:6][CH3:7])=[O:4])[C:11]1[CH:12]=[CH:13][CH:14]=[CH:15][CH:16]=1

Participants

6

Reactant 4

HCID 8471TriethylamineHCID 8793BenzathineHCID 97945Ethyl 2,3-dibromopropionateHCID 2734074Triethylammonium bromide

Product 1

HCID 2736402Ethyl 1,4-dibenzylpiperazine-2-carboxylateYield 89%

Reagents, catalysts & solvents 1

HCID 241BenzeneSolvent2×

Procedure

80 g (0.31 mol) of ethyl 2,3-dibromopropionate diluted in 300 ml of benzene are added dropwise, but fairly rapidly, to a warm solution of 72 g (0.3 mol) of N,N'-dibenzylethylenediamine, 700 ml of benzene and 50 ml (0.36 mol) of triethylamine. After the addition, reflux is maintained for 3 hours (triethylamine hydrobromide precipitates in the reaction mixture). The mixture is cooled and filtered through fritted glass, and the solid is washed with ether. The flitrate is washed with 200 ml of saturated sodium hydrogen carbonate solution and then twice with 100 ml of water. The organic phases are dried over magnesium sulfate and the solvents are evaporated off in vacuo. Approximately 100 ml of toluene are added, and evaporation is continued. The resulting residue is diluted in 400 ml of absolute ethanol and saturated with gaseous hydrogen chloride. The salt precipitates by the addition of ether. Filtering, washing with ether and drying yield from 100 to 110 g of white crystals.

Workup

  1. additionare added dropwise
  2. additionAfter the addition
  3. temperaturereflux
  4. customprecipitates in the reaction mixture)
  5. temperatureThe mixture is cooled
  6. filtrationfiltered through fritted glass
  7. washthe solid is washed with ether
  8. washThe flitrate is washed with 200 ml of saturated sodium hydrogen carbonate solution
  9. dry with materialThe organic phases are dried over magnesium sulfate
  10. customthe solvents are evaporated off in vacuo
  11. additionApproximately 100 ml of toluene are added
  12. customevaporation
  13. additionThe resulting residue is diluted in 400 ml of absolute ethanol and saturated with gaseous hydrogen chloride
  14. customThe salt precipitates by the addition of ether
  15. filtrationFiltering
  16. washwashing with ether
  17. customdrying

Sources & evidence

ORD record
ord-31713ec3ac3f459faf5d84abb9f38c8c
Source dataset
uspto-grants-1996_02
Patent number
US05492912

Reaction notes

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