Hydroxyamine hydrochloride → 5-(hydroxyiminomethyl)-1-tert-butyl-1H-pyrazole-4-carboxylic acid, ethyl ester
Reaction equation
Cl.[NH2:2][OH:3].[CH:4]([C:6]1[N:10]([C:11]([CH3:14])([CH3:13])[CH3:12])[N:9]=[CH:8][C:7]=1[C:15]([O:17][CH2:18][CH3:19])=[O:16])=O>C(O)C>[OH:3][N:2]=[CH:4][C:6]1[N:10]([C:11]([CH3:14])([CH3:13])[CH3:12])[N:9]=[CH:8][C:7]=1[C:15]([O:17][CH2:18][CH3:19])=[O:16]Participants
4
Procedure
Hydroxylamine hydrochloride (4.3 grams, 0.062 mole) was added to a cold solution of 5-formyl-1-tert-butyl-1H-pyrazole-4-carboxylic acid, ethyl ester (7 grams, 0.031 mole) in absolute ethanol (40 ml). The reaction mixture was stirred in the cold for thirty minutes, then at room temperature for 16 hours. The reaction mixture was then poured over ice-water, and the precipitated product was separated, dried, and recrystallized from toluene, yielding 3 grams of 5-(hydroxyiminomethyl)-1-tert-butyl-1H-pyrazole-4-carboxylic acid, ethyl ester, m.p., 105° C.-107° C.