4-Methoxyphenylhydrazine hydrochloride → HCID 66738820, compound

Participants

Reaction Conditions

Reaction Steps

(Z)—N-(3-(dimethylamino)-2-(trifluoromethyl)allylidene)-N-methyl methanaminium hexafluorophosphate (4.46 g, 13.1 mmol) and 4-methoxyphenyl hydrazine hydrochloride (2.55 g, 14.6 mmol) were suspended in tetrahydrofuran (50 mL) and cooled to 0° C. Sodium methoxide (820 mg, 14 mmol) was added as a solid in one portion. The mixture was stirred at 0° C. for 10 minutes. The ice bath was removed and the mixture was stirred at room temperature for 1 hour. The mixture was cooled again to 0° C. and trifluoroacetic acid (3 mL) was added. The ice bath was removed and the mixture heated to reflux. After 18 hours at reflux, the reaction was cooled to room temperature and diluted with ethyl acetate (50 mL). The mixture was washed successively with saturated sodium bicarbonate until the washings were basic. The combined aqueous washings were extracted with ethyl acetate. The combined organic layers were washed with brine, dried over magnesium sulfate, filtered and concentrated. The crude material was passed through a plug of silica gel (100 g), eluting with dichloromethane (600 mL). The filtrate was concentrated to give 1-(4-methoxyphenyl)-4-(trifluoromethyl)-1H-pyrazole (2.7 g, 85%). 1H NMR (400 MHz, CDCl3, δ): 8.06 (s, 1H), 7.85 (s, 1H), 7.53-7.59 (m, 2H), 6.94-7.00 (m, 2H), 3.84 (s, 3H).

Provenance & Evidence