Ethylenediamine → 2-Piperazinone, 3,3-dimethyl-

HRID 2096310Notes

Reaction equation

HRID 2096310 reaction equation
C(=O)([O-])[O-].[K+].[K+].[CH2:7]([NH2:10])[CH2:8][NH2:9].Br[C:12]([CH3:19])([CH3:18])[C:13]([O:15]CC)=O>C1(C)C=CC=CC=1>[CH3:19][C:12]1([CH3:18])[NH:10][CH2:7][CH2:8][NH:9][C:13]1=[O:15]

Participants

5

Reactant 3

HCID 3301EthylenediamineHCID 11430Potassium CarbonateHCID 11745Propanoic acid, 2-bromo-2-methyl-, ethyl ester

Product 1

HCID 2111572-Piperazinone, 3,3-dimethyl-

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent2×

Procedure

Potassium carbonate (390 grams) and ethylene diamine (1001 grams) are stirred with toluene (1.50 l). A solution of ethyl 2-bromoisobutyrate (500 grams) in toluene (750 ml) is added. The suspension is heated to reflux over night, and filtered. The filter cake is washed with toluene (500 ml). The combined filtrates (volume 4.0 l) are heated on a water bath and distilled at 0.3 atm. using a Claisen apparatus; first 1200 ml distillate is collected at 35° C. (the temperature in the mixture is 75° C.). More toluene is added (600 ml), and another 1200 ml distillate is collected at 76° C. (the temperature in the mixture is 80° C.). Toluene (750 ml) is added again, and 1100 ml of distillate is collected at 66° C. (temperature in the mixture 71° C.). The mixture is stirred on an ice bath and inoculated, whereby the product precipitates. The product is isolated by filtration, washed with toluene, and dried over night in a vacuum oven at 50° C. Yield 171 g (52%) of 3,3-dimethylpiperazin-2-one. NMR consistent with structure.

Workup

  1. temperatureThe suspension is heated
  2. temperatureto reflux over night
  3. filtrationfiltered
  4. washThe filter cake is washed with toluene (500 ml)
  5. temperatureThe combined filtrates (volume 4.0 l) are heated on a water bath
  6. distillationdistilled at 0.3 atm.
  7. distillationfirst 1200 ml distillate is collected at 35° C. (the temperature in the mixture
  8. customis 75° C.
  9. additionMore toluene is added (600 ml)
  10. distillationanother 1200 ml distillate is collected at 76° C. (the temperature in the mixture
  11. customis 80° C.
  12. additionToluene (750 ml) is added again
  13. distillation1100 ml of distillate is collected at 66° C. (temperature in the mixture 71° C.)
  14. customwhereby the product precipitates
  15. customThe product is isolated by filtration
  16. washwashed with toluene
  17. customdried over night in a vacuum oven at 50° C

Sources & evidence

ORD record
ord-33195b227fcf4b499ab25c613d4ed9d0
Source dataset
uspto-grants-2013_05
Patent number
US08450324B2

Reaction notes

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