Tetramethoxypropane → 1-(4-chlorophenyl)-1H-pyrazole

HRID 2172152Notes

Reaction equation

HRID 2172152 reaction equation
Cl.[Cl:2][C:3]1[CH:8]=[CH:7][C:6]([NH:9][NH2:10])=[CH:5][CH:4]=1.CO[CH:13](OC)[CH2:14][CH:15](OC)OC.C([O-])(=O)C.[Na+].C(=O)(O)[O-].[Na+]>C(O)(=O)C.O>[Cl:2][C:3]1[CH:8]=[CH:7][C:6]([N:9]2[CH:15]=[CH:14][CH:13]=[N:10]2)=[CH:5][CH:4]=1

Participants

7

Reactant 4

HCID 66019TetramethoxypropaneHCID 71600Hydrazine, (4-chlorophenyl)-, hydrochloride (1:1)HCID 516892Sodium BicarbonateHCID 517045Sodium Acetate

Product 1

HCID 122381321-(4-chlorophenyl)-1H-pyrazole

Reagents, catalysts & solvents 2

HCID 176Acetic AcidSolventHCID 962WaterSolvent

Procedure

A solution of 4-chlorophenylhydrazine hydrochloride (2.02 g, 11.3 mmol), 1,1,3,3-tetramethoxypropane (2.00 mL, 12.1 mmol) and sodium acetate (1.00 g, 12.2 mmol) in acetic acid (25 mL) is heated to gentle reflux overnight. The solution is cooled and poured into water (125 mL). Solid sodium bicarbonate is added in portions until the pH of the mixture is slightly basic. This is then extracted twice with ethyl acetate (125 mL), and the extracts are washed with brine, combined, dried over anhydrous magnesium sulfate, filtered and evaporated to afford 1-(4-chlorophenyl)pyrazole in two crops (1.13 g+0.24 g, 7.65 mmol, 68%). m.p. 50-53° C. TLC RF 0.19 (10:90 ethyl acetate-hexane), 1H NMR (300 MHz, CDCl3): δ 7.89 (1H, dd, J=2.4, 0.6 Hz), 7.72 (1H, d, J=1.5 Hz), 7.64 (2H, d, J=8.7 Hz), 7.42 (2H, d, J=8.7 Hz), 6.47 (1H, dd, J=2.4, 1.8 Hz). MS (ES+): m/e 182 (3), 181 (34), 180 (6), 179 (100).

Workup

  1. temperatureto gentle reflux overnight
  2. temperatureThe solution is cooled
  3. extractionThis is then extracted twice with ethyl acetate (125 mL)
  4. washthe extracts are washed with brine
  5. dry with materialdried over anhydrous magnesium sulfate
  6. filtrationfiltered
  7. customevaporated

Sources & evidence

ORD record
ord-48f72643e2fc405880e1f4a4739d7375
Source dataset
uspto-grants-2015_06
Patent number
US09051342B2

Reaction notes

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