Benzyl Bromide → ethyl 1-benzyl-1H-pyrazole-4-carboxylate

HRID 1363311Notes

Reaction equation

HRID 1363311 reaction equation
[H-].[Na+].[NH:3]1[CH:7]=[C:6]([C:8]([O:10][CH2:11][CH3:12])=[O:9])[CH:5]=[N:4]1.[CH2:13](Br)[C:14]1[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=1>C1COCC1>[CH2:13]([N:3]1[CH:7]=[C:6]([C:8]([O:10][CH2:11][CH3:12])=[O:9])[CH:5]=[N:4]1)[C:14]1[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=1

Participants

5

Reactant 3

HCID 7498Benzyl BromideHCID 24758Sodium hydrideHCID 142179ethyl 1H-pyrazole-4-carboxylate

Product 1

HCID 15237993ethyl 1-benzyl-1H-pyrazole-4-carboxylateYield 98%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

To a stirred suspension of NaH (53 mg, 1.33 mmol, 60% dispersion in mineral oil) in THF (5 mL), was added dropwise over 3 min a solution of ethyl 1H-pyrazole-4-carboxylate (155 mg, 1.11 mmol). The mixture was stirred at rt for 45 min and then treated with benzyl bromide (neat). After 2 h, the reaction was quenched with saturated solution of NH4Cl and extracted with EtOAc (3×50 mL). The combined organic layers were washed with water, brine, dried (Na2SO4), filtered and concentrated. Purification by flash chromatography (Isco CombiFlash) 0-60% EtOAc/heptane provided ethyl 1-benzyl-1H-pyrazole-4-carboxylate (256 mg, 98%). 1H NMR (400 MHz, CDCl3) δ ppm 1.33 (t, J=7.09 Hz, 3H), 4.28 (q, J=7.08 Hz, 2H), 5.31 (s, 2H), 7.24-7.28 (m, 2H), 7.31-7.42 (m, 3H), 7.86 (s, 1H), 7.95 (s, 1H); LCMS-MS (ESI+) 230.80 (M+H).

Workup

  1. waitAfter 2 h
  2. customthe reaction was quenched with saturated solution of NH4Cl
  3. extractionextracted with EtOAc (3×50 mL)
  4. washThe combined organic layers were washed with water, brine
  5. dry with materialdried (Na2SO4)
  6. filtrationfiltered
  7. concentrationconcentrated
  8. customPurification by flash chromatography (Isco CombiFlash) 0-60% EtOAc/heptane

Sources & evidence

ORD record
ord-1d8a0215ebdc475594351ba0c1af6359
Source dataset
uspto-grants-2011_02
Patent number
US07884124B2

Reaction notes

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