tert-Butylhydrazine monohydrochloride → ethyl 1-tert-butyl-5-methyl-1H-pyrazole-4-carboxylate

HRID 1930382Notes

Reaction equation

HRID 1930382 reaction equation
Cl.[C:2]([NH:6][NH2:7])([CH3:5])([CH3:4])[CH3:3].CN([CH:11]=[C:12]([C:18](=O)[CH3:19])[C:13]([O:15][CH2:16][CH3:17])=[O:14])C>C(O)C.CCOCC>[C:2]([N:6]1[C:18]([CH3:19])=[C:12]([C:13]([O:15][CH2:16][CH3:17])=[O:14])[CH:11]=[N:7]1)([CH3:5])([CH3:4])[CH3:3]

Participants

5

Reactant 2

HCID 81889tert-Butylhydrazine monohydrochlorideHCID 3806790Ethyl 2-acetyl-3-(dimethylamino)acrylate

Product 1

HCID 13654177ethyl 1-tert-butyl-5-methyl-1H-pyrazole-4-carboxylateYield 65.2%

Reagents, catalysts & solvents 2

HCID 702EthanolSolventHCID 3283Diethyl EtherSolvent

Procedure

In ethanol (10 mL) was placed the tert-butylhydrazine hydrochloride (1.35 g, 10.8 mmol) and ethyl 2-((dimethylamino)methylene)-3-oxobutanoate (2.00 g, 10.8 mmol). The mixture warmed to reflux and stirred for 2 hrs, cooled to RT and stirred overnight. The mixture was evaporated at reduced pressure to give an oil which was dissolved in ether (25 mL) and washed successively with water (25 mL), saturated sodium bicarbonate (25 mL) and brine (25 mL), dried (Na2SO4), evaporated at reduced pressure and purified by chromatography (Biotage S1-25 column, 10-40% ethyl acetate/Hex) to give ethyl 1-tert-butyl-5-methyl-1 H-pyrazole-4-carboxylate (1.48 g, 65% yield) as an oil. MS (ESI) m/z: 211.0 (M+H+).

Workup

  1. temperatureThe mixture warmed
  2. temperatureto reflux
  3. stirringstirred overnight
  4. customThe mixture was evaporated at reduced pressure
  5. customto give an oil which
  6. washwashed successively with water (25 mL), saturated sodium bicarbonate (25 mL) and brine (25 mL)
  7. dry with materialdried (Na2SO4)
  8. customevaporated at reduced pressure
  9. custompurified by chromatography (Biotage S1-25 column, 10-40% ethyl acetate/Hex)

Sources & evidence

ORD record
ord-b0ef4411425945d1932c503ccb9327ec
Source dataset
uspto-grants-2012_05
Patent number
US08188113B2

Reaction notes

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