2,3,4-Trichloroaniline → 2,3,4-Trichlorophenylhydrazine

Fifty grams of 2,3,4-trichloroaniline was added portionwise to a solution of 200 ml of concentrated hydrochloric acid at approximately 0° C. To the reaction mixture was added 17.6 g of sodium nitrite dissolved in 100 ml of water dropwise over 1 hour. Next, 94.8 g of stannous chloride dissolved in 100 ml of concentrated hydrochloric acid was added dropwise to the reaction mixture over a 1 hour period while maintaining the temperature at approximately 0° C. The reaction mixture was stirred for approximately 1 hour at this temperature and then warmed to room temperature and stirred for 20 additional hours. The precipitated solid was collected by filtration and dried. The collected solid was added to a cold solution of 300 ml of 25% aqueous sodium hydroxide and this solution was stirred at approximately 5° C. for 1 hour. This aqueous solution was then extracted with ether and the organic phase was washed with water and saturated sodium chloride, and finally dried over anhydrous magnesium sulfate. The organic phase was evaporated under reduced pressure and the residue was recrystallized from ethanol to afford 35 g of 2,3,4-trichlorophenylhydrazine. Yield 66%. mp=138°-140° C.

1. additionwas added dropwise to the reaction mixture over a 1 hour period
2. temperaturewarmed to room temperature
3. stirringstirred for 20 additional hours
4. filtrationThe precipitated solid was collected by filtration
5. customdried
6. additionThe collected solid was added to a cold solution of 300 ml of 25% aqueous sodium hydroxide
7. stirringthis solution was stirred at approximately 5° C. for 1 hour
8. extractionThis aqueous solution was then extracted with ether
9. washthe organic phase was washed with water and saturated sodium chloride
10. dry with materialfinally dried over anhydrous magnesium sulfate
11. customThe organic phase was evaporated under reduced pressure
12. customthe residue was recrystallized from ethanol

ORD record

ord-1891df7cb58c41489dafcb595664485a

Source dataset

uspto-grants-1986_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04563210