Hydrochloric Acid → Mixture of (1,3-Dimethylpyrazole + 1,5-Dimethylpyrazole)

HRID 1894052Notes

Reaction equation

HRID 1894052 reaction equation
CNN.COC(OC)CC(=O)C.Cl.[CH3:14][N:15]1[CH:19]=[CH:18][C:17]([CH3:20])=[N:16]1.[CH3:21][N:22]1[C:26]([CH3:27])=[CH:25][CH:24]=[N:23]1>>[CH3:14][N:15]1[CH:19]=[CH:18][C:17]([CH3:20])=[N:16]1.[CH3:21][N:22]1[C:26]([CH3:27])=[CH:25][CH:24]=[N:23]1

Participants

6

Reactant 5

HCID 313Hydrochloric AcidHCID 6061MethylhydrazineHCID 790961H-Pyrazole, 1,3-dimethyl-HCID 1365021,5-DimethylpyrazoleHCID 2285484,4-Dimethoxy-2-butanone

Product 1

HCID 67389620Mixture of (1,3-Dimethylpyrazole + 1,5-Dimethylpyrazole)

Procedure

Methylhydrazine (4.25 mL, 80 mmol) was added to 4,4-dimethoxy-2-butanone (10.63 mL, 80 mmol) with keeping the temperature below 25° C. and the mixture was stirred at r.t. for 16 h. The mixture was poured in aq HCl (6N, 16 mL, 1.2 equiv) with stirring. The MeOH was removed in vacuo and then 50% aqueous NaOH was added until the pH was basic. The mixture was extracted with diethyl ether (3 times). The organic phases were combined, dried (Na2SO4) and concentrated in vacuo to afford a mixture of 1,3-dimethyl-1H-pyrazole and 1,5-dimethyl-1H-pyrazole (4:1 NMR ratio) (7.32 g, 95%) as a yellow syrup which was used in the next step without further purification.

Workup

  1. customthe temperature below 25° C.
  2. stirringwith stirring
  3. customThe MeOH was removed in vacuo
  4. addition50% aqueous NaOH was added until the pH
  5. extractionThe mixture was extracted with diethyl ether (3 times)
  6. dry with materialdried (Na2SO4)
  7. concentrationconcentrated in vacuo
  8. customto afford
  9. customwas used in the next step without further purification

Sources & evidence

ORD record
ord-03d196f8408a445a9672b503d5f618bd
Source dataset
uspto-grants-2013_08
Patent number
US08513268B2

Reaction notes

Loading…