Ethylenediamine → 3-Phenylpiperazin-2-one

HRID 622775Notes

Reaction equation

HRID 622775 reaction equation
[CH2:1]([NH2:4])[CH2:2][NH2:3].Br[CH:6]([C:12]1[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=1)[C:7]([O:9]CC)=O>C(O)C>[C:12]1([CH:6]2[NH:4][CH2:1][CH2:2][NH:3][C:7]2=[O:9])[CH:13]=[CH:14][CH:15]=[CH:16][CH:17]=1

Participants

4

Reactant 2

HCID 3301EthylenediamineHCID 97780Ethyl bromophenylacetate

Product 1

HCID 2506813-Phenylpiperazin-2-oneYield 54.3%

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent2×

Procedure

To a stirred solution of 1928 g (32.1 mol) of ethylenediamine in 2 liters of absolute ethanol was added a solution of 3130 g (12.8 mol) of ethyl α-bromophenylacetate in 4 liters of absolute ethanol at such a rate so as to maintain reflux (~45 minutes addition time). The mixture was allowed to cool to ambient temperature and then concentrated to a thick yellow slurry. The slurry was stirred with 2 liters of chloroform, filtered, and the solid washed thoroughly with chloroform (total of 8 liters). The filtrate was concentrated to near dryness and the resulting residue stirred for a short time with 2 liters of isopropanol. The solid was collected by filtration, washed with 4 liters of isopropanol, and dried to give 1224 g (54%) of 3-phenyl-2-piperazinone. This material was used as such in the next step. [Pure material could be obtained by recrystallization from benzene and then from acetone to give a white solid (mp. 139.0°-139.5° C. ).]

Workup

  1. temperatureto maintain
  2. temperaturereflux
  3. addition(~45 minutes addition time)
  4. concentrationconcentrated to a thick yellow slurry
  5. filtrationfiltered
  6. washthe solid washed thoroughly with chloroform (total of 8 liters)
  7. concentrationThe filtrate was concentrated
  8. stirringthe resulting residue stirred for a short time with 2 liters of isopropanol
  9. filtrationThe solid was collected by filtration
  10. washwashed with 4 liters of isopropanol
  11. customdried

Sources & evidence

ORD record
ord-8e8d9d0d0f414f819662d27866224cc5
Source dataset
uspto-grants-1988_09
Patent number
US04772705

Reaction notes

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