反应详情

温度

70 °C

To a solution of (4-bromo-3-methoxyphenyl)hydrazine (62 g, 245 mmol) in ethanol (310 mL) was added tetramethoxypropane (40.2 g, 245 mmol) over a few minutes, and the mixture was heated to an internal temperature of 70° C. The mixture was stirred at 70° C. for 1.5 h then slowly cooled to RT. Ethanol was removed in vacuo and the residue was slurried in EtOAc. The residue was neutralized with 1 M aqueous sodium hydroxide (˜700 mL) to cause precipitation. The biphasic mixture was filtered and the filtrate was extracted with EtOAC, dried over sodium sulfate and concentrated to provide 30 g of 1-(4-bromo-3-methoxyphenyl)-1H-pyrazole as a black solid (30 g, MS: 254 [M+H+].).

1. temperaturethen slowly cooled to RT
2. customEthanol was removed in vacuo
3. customprecipitation
4. filtrationThe biphasic mixture was filtered
5. extractionthe filtrate was extracted with EtOAC
6. dry with materialdried over sodium sulfate
7. concentrationconcentrated