Trifluoroacetic acid → 1-(Naphthalene-2-sulfonyl)-piperazine

HRID 1392967Notes

Reaction equation

HRID 1392967 reaction equation
C([N:8]1[CH2:13][CH2:12][NH:11][CH2:10][CH2:9]1)(OC(C)(C)C)=O.[CH:14]1[C:23]2[C:18](=[CH:19][CH:20]=[CH:21][CH:22]=2)[CH:17]=[CH:16][C:15]=1[S:24](Cl)(=[O:26])=[O:25].FC(F)(F)C(O)=O>C(Cl)Cl.CC(N(CC)C(C)C)C>[CH:14]1[C:23]2[C:18](=[CH:19][CH:20]=[CH:21][CH:22]=2)[CH:17]=[CH:16][C:15]=1[S:24]([N:8]1[CH2:9][CH2:10][NH:11][CH2:12][CH2:13]1)(=[O:25])=[O:26]

Participants

6

Reactant 3

HCID 6422Trifluoroacetic acidHCID 71252-Naphthalenesulfonyl chlorideHCID 143452tert-Butyl piperazine-1-carboxylate

Product 1

HCID 7039571-(Naphthalene-2-sulfonyl)-piperazineYield 97.8%

Reagents, catalysts & solvents 2

HCID 6344DichloromethaneSolvent3×HCID 81531DiisopropylethylamineSolvent

Procedure

A solution of N-tert-butyoxycarbonylpiperazine (2a) (1.86 g) in DCM (100 mL) and N,N-di-2-propyl-ethylamine (2 mL) was cooled in ice-water as a solution of 2-naphthalenesulfonylchloride (2.27 g) in DCM (50 mL) was added drop-wise. After addition, the cooling was removed and the reaction stirred overnight. The solvent was evaporated and the residue partitioned between water and ethyl acetate. The organic phase was sequentially washed with 0.5 N hydrochloric acid, water, saturated aqueous sodium bicarbonate and brine. After drying, the solvent was evaporated to provide a white solid. The white solid was dissolved in DCM (35 mL) and treated with trifluoroacetic acid (15 mL). After one hour, the solvent was evaporated, the residue suspended in water and the solution made basic with 1 N sodium hydroxide. The mixture was extracted with ethyl acetate. The extracts were washed with water, dried, and the solvent evaporated to give a white solid (2.7 g).

Workup

  1. additionwas added drop-wise
  2. additionAfter addition
  3. customthe cooling was removed
  4. customThe solvent was evaporated
  5. customthe residue partitioned between water and ethyl acetate
  6. washThe organic phase was sequentially washed with 0.5 N hydrochloric acid, water, saturated aqueous sodium bicarbonate and brine
  7. customAfter drying
  8. customthe solvent was evaporated
  9. customto provide a white solid
  10. waitAfter one hour
  11. customthe solvent was evaporated
  12. extractionThe mixture was extracted with ethyl acetate
  13. washThe extracts were washed with water
  14. customdried
  15. customthe solvent evaporated

Sources & evidence

ORD record
ord-78dfa9a598fc4c928dbe8e7b35f323ec
Source dataset
uspto-grants-2008_03
Patent number
US07345043B2

Reaction notes

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