2,6-Dichloro-4-fluoroaniline → (2,6-Dichloro-4-fluorophenyl)hydrazine

9.0 g (0.05 mol) of 2,6-dichloro-4-fluoroaniline was added to 50 ml of concentrated hydrochloric acid, and a solution of 3.8 g (0.055 mol) of sodium nitrite in 25 ml of water was dropwise added thereto at a temperature of from 0° to 5° C. After completion of the dropwise addition, the mixture was stirred at the same temperature for further 1 hour. Insolubles were removed by filtration, and the filtrate was dropwise added at a temperature of from 0° to 10° C. to a solution of 33.8 g (0.15 mol) of stannous chloride dihydrate in 50 ml of concentrated hydrochloric acid. After completion of the dropwise addition, the mixture was stirred at the same temperature for further 2 hours. The precipitated hydrochloride was collected by filtration, and 50 ml of water was added thereto. The mixture was made alkaline with an addition of 20% sodium hydroxide, and the precipitated solid was extracted with ethyl ether. The ethyl ether layer was washed with water and dried over anhydrous sodium sulfate. Then, the solvent was distilled off. The residue thereby obtained was washed with cold n-hexane to obtain 6.9 g (yield: 70.4%) of the desired compound as white feather-like crystals. Melting point: 117°-119° C.

1. customof from 0° to 5° C
2. additionAfter completion of the dropwise addition
3. customInsolubles were removed by filtration
4. additionAfter completion of the dropwise addition
5. stirringthe mixture was stirred at the same temperature for further 2 hours
6. filtrationThe precipitated hydrochloride was collected by filtration, and 50 ml of water
7. additionwas added
8. additionwith an addition of 20% sodium hydroxide
9. extractionthe precipitated solid was extracted with ethyl ether
10. washThe ethyl ether layer was washed with water
11. dry with materialdried over anhydrous sodium sulfate
12. distillationThen, the solvent was distilled off
13. customThe residue thereby obtained
14. washwas washed with cold n-hexane

ORD record

ord-6ca8d50d50fb4d6d82945c174057b1d6

Source dataset

uspto-grants-1990_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04925864