反应详情

温度

-5 °C

Step 1 A solution of sodium nitrite (2.448 g, 35.5 mmol) in water (12 mL) was added dropwise to a suspension of 2-amino-4-bromobenzoic acid (7.30 g, 33.8 mmol) in concentrated hydrochloric acid (34 mL) at −5° C., at such rate that the temperature did not exceed 0° C. The resulting suspension was stirred at −5° C. for 10 min and was then added dropwise to a rapidly stirred solution of tin (II) chloride (13.46 g, 71.0 mmol) in concentrated hydrochloric acid (10 mL) at −5° C., at such a rate that the temperature did not exceed 0° C. The resulting suspension was warmed to rt and stirred for 1 h. The precipitate was collected by filtration, washed with water, and dried to provide 4-bromo-2-hydrazinylbenzoic acid hydrochloric acid salt as a pale tan solid (7.79 g, 86%). 1H NMR (400 MHz, DMSO-d6) δ 9.14 (br. s., 1H) 7.79 (d, J=8.35 Hz, 1H) 7.34 (d, J=1.76 Hz, 1H) 7.13 (dd, J=8.35, 1.76 Hz, 1H). Mass spectrum m/z 231, 233 (M+H)+.

1. customdid not exceed 0° C
2. customdid not exceed 0° C
3. temperatureThe resulting suspension was warmed to rt
4. stirringstirred for 1 h
5. filtrationThe precipitate was collected by filtration
6. washwashed with water
7. customdried