Trifluoroacetic acid → 1-Benzylpiperazine-2-thione

HRID 609652Notes

Reaction equation

HRID 609652 reaction equation
[CH2:1]([N:8]1[CH2:13][CH2:12][N:11](C(OC(C)(C)C)=O)[CH2:10][C:9]1=[S:21])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.FC(F)(F)C(O)=O>C(Cl)Cl>[CH2:1]([N:8]1[CH2:13][CH2:12][NH:11][CH2:10][C:9]1=[S:21])[C:2]1[CH:3]=[CH:4][CH:5]=[CH:6][CH:7]=1

Participants

4

Reactant 2

HCID 6422Trifluoroacetic acidHCID 195997511-Benzyl-4-(tert-butyloxycarbonyl)piperazin-2-thione

Product 1

HCID 106083781-Benzylpiperazine-2-thioneYield 87%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

To a solution of 1-benzyl-4-(tert-butyloxycarbonyl)piperazin-2-thione (925 mg, 3.02 mmol) in CH2Cl2 (25 mL) was added trifluoroacetic acid (2.5 mL). The mixture was stirred at room temperature, under nitrogen, for 2 h. The solvent was evaporated and the residue azeotroped with toluene (2×10 mL). The residue was partitioned between CH2Cl2 (2×50 mL) and Na2CO3 solution (10% (w/v), 40 mL). The combined organic layers were dried Na2SO4) and evaporated. The residue was chromatographed on silica, eluting with CH2Cl2 :MeOH (95:5) to afford the title compound (539 mg, 87%) as a pale orange solid. mp. 70-73° C. 1H NMR (250 MHz, CDCl3) δ3.11-3.16 (2H, m), 3.29-3.33 (2H, m), 4.10 (2H, s), 5.31 (2H, s), 7.30-7.37 (5H, m). MS (ES+) (207, M+1).

Workup

  1. customThe solvent was evaporated
  2. customthe residue azeotroped with toluene (2×10 mL)
  3. customThe residue was partitioned between CH2Cl2 (2×50 mL) and Na2CO3 solution (10% (w/v), 40 mL)
  4. customevaporated
  5. customThe residue was chromatographed on silica
  6. washeluting with CH2Cl2 :MeOH (95:5)

Sources & evidence

ORD record
ord-7c7f290acf49428ea589da940fa44900
Source dataset
uspto-grants-1999_12
Patent number
US05998415

Reaction notes

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