Hydrochloric Acid → 3-Bromo-2-chloro-4,5-difluoroaniline

To a suspension of iron powder (38.6 g) in water (40 ml), with stirring vigorously at 50° to 60° C., was slowly added concentrated hydrochloric acid (5 ml). After mixed with ethanol (100 ml), 3-bromo-2-chloro-4,5-difluoronitrobenzene (58.8 g) was added portionwise to the suspension at 60° to 75° C. during 30 minutes. After stirring for 70 minutes, the hot reaction mixture was filtered and the insoluble materials were washed with hot ethanol (30 ml) and with benzene (100 ml) successively. The filtrate and washings were combined and mixed with ice water. The resulting organic layer was washed with water, dried over anhydrous sodium sulfate and then concentrated. The resulting residue was purified by silica gel chromatography eluting with dichloromethane-n-hexane (1:1) to give the title compound (34.5 g) as light brown prisms, mp 83°-86° C.

1. additionwas added portionwise to the suspension at 60° to 75° C. during 30 minutes
2. stirringAfter stirring for 70 minutes
3. filtrationthe hot reaction mixture was filtered
4. washthe insoluble materials were washed with hot ethanol (30 ml) and with benzene (100 ml) successively
5. additionmixed with ice water
6. washThe resulting organic layer was washed with water
7. dry with materialdried over anhydrous sodium sulfate
8. concentrationconcentrated
9. customThe resulting residue was purified by silica gel chromatography
10. washeluting with dichloromethane-n-hexane (1:1)

ORD-Eintrag

ord-69fa1493a5764bc69e6551eb2ac2840e

Quelldatensatz

uspto-grants-1988_11

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US04788320