Potassium Hydroxide → 4-(3,4-Dibromo-benzyl)-piperazine-1-carboxylic acid tert-butyl ester

HRID 1817065Notes

Reaction equation

HRID 1817065 reaction equation
[C:1]([O:5][C:6]([N:8]1[CH2:13][CH2:12][NH:11][CH2:10][CH2:9]1)=[O:7])([CH3:4])([CH3:3])[CH3:2].[Br:14][C:15]1[CH:16]=[C:17]([CH:20]=[CH:21][C:22]=1[Br:23])[CH:18]=O.[BH-](OC(C)=O)(OC(C)=O)OC(C)=O.[Na+].[OH-].[K+]>C(Cl)Cl>[C:1]([O:5][C:6]([N:8]1[CH2:13][CH2:12][N:11]([CH2:18][C:17]2[CH:20]=[CH:21][C:22]([Br:23])=[C:15]([Br:14])[CH:16]=2)[CH2:10][CH2:9]1)=[O:7])([CH3:4])([CH3:2])[CH3:3]

Participants

6

Reactant 4

HCID 14797Potassium HydroxideHCID 143452tert-Butyl piperazine-1-carboxylateHCID 6220533,4-DibromobenzaldehydeHCID 5049666Sodium triacetoxyborohydride

Product 1

HCID 578808894-(3,4-Dibromo-benzyl)-piperazine-1-carboxylic acid tert-butyl esterYield 73.5%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

A solution of piperazine-1-carboxylic acid tert-butyl ester (3.5 g) and 3,4-dibromobenzaldehyde (5.0 g) in DCM (80 mL) was treated with NaB(OAc)3H (5.6 g). After 16 h, the resulting mixture was treated with 10% aq. KOH (80 mL). The aqueous phase was extracted with DCM (1×80 mL). The organic extracts were combined and dried (MgSO4). Most of the solvent was removed by concentration. Upon standing overnight, the resulting mixture produced crystals that were filtered and washed with DCM (1×5 mL), giving the title compound as a white crystalline solid (6.0 g).

Workup

  1. extractionThe aqueous phase was extracted with DCM (1×80 mL)
  2. dry with materialdried (MgSO4)
  3. customMost of the solvent was removed by concentration
  4. waitUpon standing overnight
  5. customthe resulting mixture produced crystals that
  6. filtrationwere filtered
  7. washwashed with DCM (1×5 mL)

Sources & evidence

ORD record
ord-3031731617d240ff88750ac5ce09fa4c
Source dataset
uspto-grants-2009_10
Patent number
US07598249B2

Reaction notes

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