Iodoethane → tert-Butyl 4-ethyl-3-oxopiperazine-1-carboxylate

HRID 1108575Notes

Reaction equation

HRID 1108575 reaction equation
[C:1]([O:5][C:6]([N:8]1[CH2:13][CH2:12][NH:11][C:10](=[O:14])[CH2:9]1)=[O:7])([CH3:4])([CH3:3])[CH3:2].[CH3:15][C:16](C)([O-])C.[K+].ICC>CN(C=O)C>[C:1]([O:5][C:6]([N:8]1[CH2:13][CH2:12][N:11]([CH2:15][CH3:16])[C:10](=[O:14])[CH2:9]1)=[O:7])([CH3:4])([CH3:2])[CH3:3]

Participants

5

Reactant 3

HCID 6340Iodoethane2×HCID 3157178Tert-butyl 3-oxopiperazine-1-carboxylateHCID 23665647Potassium tert-butoxide

Product 1

HCID 18783917tert-Butyl 4-ethyl-3-oxopiperazine-1-carboxylateYield 70.2%

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Procedure

1-tert-Butoxycarbonyl-3-oxopiperazine (7.5 g) was dissolved in dry DMF (250 ml) and potassium tert-butoxide (8.4 g) was added. The mixture was stirred at ambient temperature for 30 minutes, then iodoethane (3.3 ml) added, and stirring continued at the same temperature for 24 hours. A further equal portion of iodoethane was added and stirring continued for 24 hours. Solvent was evaporated, and the residue partitioned between ethyl acetate and water. The organic layer was washed with water, evaporated, and purified by chromatography on silica, using as eluant a gradient increasing in polarity from 0 to 25% isopropanol in iso-hexane. Relevant fractions were combined and evaporated to give 1-tert-butoxycarbonyl-4-ethyl-3-oxopiperazine (6.0 g).

Workup

  1. stirringstirring
  2. waitcontinued at the same temperature for 24 hours
  3. stirringstirring
  4. waitcontinued for 24 hours
  5. customSolvent was evaporated
  6. customthe residue partitioned between ethyl acetate and water
  7. washThe organic layer was washed with water
  8. customevaporated
  9. custompurified by chromatography on silica
  10. temperaturea gradient increasing in polarity from 0 to 25% isopropanol in iso-hexane
  11. customevaporated

Sources & evidence

ORD record
ord-aa432de30c7e46eca6a4251d1934c76a
Source dataset
uspto-grants-2000_05
Patent number
US06069145

Reaction notes

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