Benzoic Acid → Tert-butyl 4-(5-phenyl-1,2,4-oxadiazol-3-yl)piperazine-1-carboxylate

HRID 888179Notes

Reaction equation

HRID 888179 reaction equation
[OH:1][NH:2][C:3](=[NH:17])[N:4]1[CH2:9][CH2:8][N:7]([C:10]([O:12][C:13]([CH3:16])([CH3:15])[CH3:14])=[O:11])[CH2:6][CH2:5]1.[C:18](O)(=O)[C:19]1[CH:24]=[CH:23][CH:22]=[CH:21][CH:20]=1.C(N=C=NC(C)C)(C)C>C(Cl)Cl.N1C=CC=CC=1>[C:19]1([C:18]2[O:1][N:2]=[C:3]([N:4]3[CH2:5][CH2:6][N:7]([C:10]([O:12][C:13]([CH3:14])([CH3:16])[CH3:15])=[O:11])[CH2:8][CH2:9]3)[N:17]=2)[CH:24]=[CH:23][CH:22]=[CH:21][CH:20]=1

Participants

6

Reactant 3

HCID 243Benzoic AcidHCID 12734DiisopropylcarbodiimideHCID 178452346tert-butyl 4-(N-hydroxyamidino)-piperazine-1-carboxylate

Product 1

HCID 11992900Tert-butyl 4-(5-phenyl-1,2,4-oxadiazol-3-yl)piperazine-1-carboxylateYield 53%

Reagents, catalysts & solvents 2

HCID 1049PyridineSolventHCID 6344DichloromethaneSolvent

Procedure

To a solution of tert-butyl 4-[(hydroxyamino)(imino)methyl]piperazine-1-carboxylate (7 g, 28.6 mmol) in anhydrous DCM (150 mL) was added benzoic acid (3.49 g, 28.6 mmol) followed by diisopropyl carbodiimide (DIC, 3.6 g, 28.6 mmol). The reaction mixture was stirred at RT for 8 hours and filtered. The filtrate was evaporated and the residue obtained was refluxed in pyridine (100 mL) for 3 hours. The solvent was removed under vacuum and the residue was dissolved in DCM. The organic layer was washed with a 10% aqueous solution of sodium bicarbonate, water and brine. The organic layer was dried and the solvent was evaporated. The residue was purified by chromatography using petrol ether/EtOAc (9/1) as eluent to afford 5 g (53%) of the title compound as a solid. TLC-Pet ether/EtOAc (9/1): Rf=0.7). HPLC purity: 96%.

Workup

  1. filtrationfiltered
  2. customThe filtrate was evaporated
  3. customthe residue obtained
  4. customThe solvent was removed under vacuum
  5. dissolutionthe residue was dissolved in DCM
  6. washThe organic layer was washed with a 10% aqueous solution of sodium bicarbonate, water and brine
  7. customThe organic layer was dried
  8. customthe solvent was evaporated
  9. customThe residue was purified by chromatography

Sources & evidence

ORD record
ord-ab035be599a8471596c50f2c78cb1f59
Source dataset
uspto-grants-2012_08
Patent number
US08247437B2

Reaction notes

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