Hydrochloric Acid → 1-Piperazinecarboxylic acid, 4-(4-aMinophenyl)-, phenylMethyl ester

HRID 2044067Notes

Reaction equation

HRID 2044067 reaction equation
[N+:1]([C:4]1[CH:9]=[CH:8][C:7]([N:10]2[CH2:15][CH2:14][N:13]([C:16]([O:18][CH2:19][C:20]3[CH:25]=[CH:24][CH:23]=[CH:22][CH:21]=3)=[O:17])[CH2:12][CH2:11]2)=[CH:6][CH:5]=1)([O-])=O.[BH4-].[Na+].Cl>CO>[NH2:1][C:4]1[CH:5]=[CH:6][C:7]([N:10]2[CH2:11][CH2:12][N:13]([C:16]([O:18][CH2:19][C:20]3[CH:21]=[CH:22][CH:23]=[CH:24][CH:25]=3)=[O:17])[CH2:14][CH2:15]2)=[CH:8][CH:9]=1

Participants

5

Reactant 3

HCID 313Hydrochloric AcidHCID 4311764Sodium borohydrideHCID 57489618HCID 57489618, compound

Product 1

HCID 574896191-Piperazinecarboxylic acid, 4-(4-aMinophenyl)-, phenylMethyl esterYield 79.3%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

To a mixture of 8.0 g benzyl 4-(4-nitrophenyl)piperazine-1-carboxylate (23.5 mmol) and 11 g CoCl2 (47 mmol) in 100 mL MeOH was added 8.6 g (225 mmol) of NaBH4 portion-wise and then stirred at rt for 1 hr. To the reaction mixture was added 3N HCl until the black precipitate dissolved. The resulting mixture was concentrated to remove MeOH and the residue was extracted twice with ether. The aqueous layer was basified with 1N NaOH and then extracted twice with ethyl acetate. The combined extracts were concentrated to give an oil that was purified by MPLC chromatography (ISCO, 50% hexane/ethyl acetate, 40 g+12 g stacked column) to give 5.8 g of benzyl 4-(4-aminophenyl)piperazine-1-carboxylate. LCMS: (M+H)+=312.25.

Workup

  1. dissolutiondissolved
  2. concentrationThe resulting mixture was concentrated
  3. customto remove MeOH
  4. extractionthe residue was extracted twice with ether
  5. extractionextracted twice with ethyl acetate
  6. concentrationThe combined extracts were concentrated
  7. customto give an oil that
  8. customwas purified by MPLC chromatography (ISCO, 50% hexane/ethyl acetate, 40 g+12 g stacked column)

Sources & evidence

ORD record
ord-a434833338d348afad4753294587e925
Source dataset
uspto-grants-2013_11
Patent number
US08586751B2

Reaction notes

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