Acetic Acid → 1-Benzyl-5-oxo-1,4,5,6-tetrahydro-cyclopentapyrazole-3-carboxylic acid tert-butyl ester

HRID 475504Notes

Reaction equation

HRID 475504 reaction equation
[C:1]([O:5][C:6](=[O:18])[C:7]([CH:9]1[CH2:13][C:12]([O:14]CC)=[CH:11][C:10]1=O)=O)([CH3:4])([CH3:3])[CH3:2].Cl.[CH2:20]([NH:27][NH2:28])[C:21]1[CH:26]=[CH:25][CH:24]=[CH:23][CH:22]=1.CC(O)=O>C(O)C>[C:1]([O:5][C:6]([C:7]1[C:9]2[CH2:13][C:12](=[O:14])[CH2:11][C:10]=2[N:27]([CH2:20][C:21]2[CH:26]=[CH:25][CH:24]=[CH:23][CH:22]=2)[N:28]=1)=[O:18])([CH3:2])([CH3:3])[CH3:4]

Participants

5

Reactant 3

HCID 176Acetic AcidHCID 14084Hydrazine, (phenylmethyl)-, hydrochloride (1:1)HCID 58713641(4-Ethoxy-2-oxo-cyclopent-3-enyl)oxo-acetic acid tert-butyl ester

Product 1

HCID 587136451-Benzyl-5-oxo-1,4,5,6-tetrahydro-cyclopentapyrazole-3-carboxylic acid tert-butyl esterYield 62.1%

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

To a solution of the intermediate from step A (2.15 g, 8.45 mmol) in ethanol (100 mL) was added benzyl hydrazine hydrochloride (1.8 g, 9.22 mmol) and HOAc (10 mL). The reaction mixture was stirred at room temperature for 16 hours and then refluxed at 70° C. for 30 minutes. The reaction was cooled to room temperature and concentrated in vacuo. The residue was dissolved in ethyl acetate and washed with water, saturated NaHCO3, and brine. The organic layer was dried over anhydrous Na2SO4 filtered and concentrated in vacuo. The residue was purified by flash chromatography (SiO2) using 30% ethyl acetate-hexanes to give the desired product (1.64 g) a brown oil.

Workup

  1. temperaturerefluxed at 70° C. for 30 minutes
  2. temperatureThe reaction was cooled to room temperature
  3. concentrationconcentrated in vacuo
  4. dissolutionThe residue was dissolved in ethyl acetate
  5. washwashed with water, saturated NaHCO3, and brine
  6. dry with materialThe organic layer was dried over anhydrous Na2SO4
  7. filtrationfiltered
  8. concentrationconcentrated in vacuo
  9. customThe residue was purified by flash chromatography (SiO2)

Sources & evidence

ORD record
ord-c726fce1cffe49cd853f5fc42cabe192
Source dataset
uspto-grants-2014_01
Patent number
US08637555B2

Reaction notes

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