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

反応式

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

参加物

反応物 5

HCID 313Hydrochloric Acid

HCID 6061Methylhydrazine

HCID 790961H-Pyrazole, 1,3-dimethyl-

HCID 1365021,5-Dimethylpyrazole

HCID 2285484,4-Dimethoxy-2-butanone

生成物 1

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

実験手順

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.