1-Chloroethyl chloroformate → (R)-2-(4-chlorophenyl)piperazine dihydrochloride

HRID 1784668Notes

Reaction equation

HRID 1784668 reaction equation
C([N:8]1[CH2:13][CH2:12][N:11](C(OC(C)(C)C)=O)[C@H:10]([C:21]2[CH:26]=[CH:25][C:24]([Cl:27])=[CH:23][CH:22]=2)[CH2:9]1)C1C=CC=CC=1.[Cl:28]C(OC(Cl)C)=O>ClCCCl>[ClH:27].[ClH:28].[Cl:27][C:24]1[CH:23]=[CH:22][C:21]([C@@H:10]2[CH2:9][NH:8][CH2:13][CH2:12][NH:11]2)=[CH:26][CH:25]=1

Participants

4

Reactant 2

HCID 5213051-Chloroethyl chloroformateHCID 53628940(R)-1-benzyl-4-(tert-butoxycarbonyl)-3-(4-chlorophenyl)piperazine

Product 1

HCID 67117377(R)-2-(4-chlorophenyl)piperazine dihydrochloride

Reagents, catalysts & solvents 1

HCID 111,2-DichloroethaneSolvent

Procedure

To a solution of (R)-1-benzyl-4-(tert-butoxycarbonyl)-3-(4-chlorophenyl)piperazine (11.6 g, 30.1 mmol) in 1,2-dichloroethane (80 ml) was added 1-chloroethyl chloroformate (4.91 ml, 45.1 mmol) at room temperature. Upon disappearance of the starting material, the reaction mixture was concentrated under reduced pressure. The residue was then dissolved in methanol (100 ml) and refluxed for 30 min. The resulting white precipitate was filtered and washed with methanol to afford (R)-2-(4-chlorophenyl)piperazine dihydrochloride, which was liberated with aqueous sodium hydroxide solution, and extracted with dichloromethane to afford (R)-2-(4-chlorophenyl)piperazine (3.04 g, 51.4%) as white solid.

Workup

  1. concentrationUpon disappearance of the starting material, the reaction mixture was concentrated under reduced pressure
  2. dissolutionThe residue was then dissolved in methanol (100 ml)
  3. temperaturerefluxed for 30 min
  4. filtrationThe resulting white precipitate was filtered
  5. washwashed with methanol

Sources & evidence

ORD record
ord-b1de0259a8a84327b9e2f24dc67382a6
Source dataset
uspto-grants-2009_03
Patent number
US07504411B2

Reaction notes

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