Benzene → 2,3-Dichloro-4,5-difluoroaniline

To a suspension of iron powder (1.9 g) in water (3 ml), with vigorous stirring at 50° to 60° C., was added concentrated hydrochloric acid (0.4 ml) slowly. After mixed with ethanol (7 ml), 2,3-dichloro-4,5-difluoronitrobenzene (2.47 g) in ethanol (3 ml) was added dropwise to the suspension at 54° to 66° C. during 20 minutes. After stirring for 4 hours at the same temperature, the hot reaction mixture mixed with benzene was filtered and the insoluble materials were washed with hot ethanol (5 ml) and with benzene (20 ml) successively. The filtrate and washings were combined and mixed with ice water. The resulting organic layer was collected, 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 (1:3) to give the title compound (0.89 g) as colorless needles, mp 94°-97.5° C.

1. additionwas added dropwise to the suspension at 54° to 66° C. during 20 minutes
2. stirringAfter stirring for 4 hours at the same temperature
3. filtrationwas filtered
4. washthe insoluble materials were washed with hot ethanol (5 ml) and with benzene (20 ml) successively
5. additionmixed with ice water
6. customThe resulting organic layer was collected
7. washwashed with water
8. dry with materialdried over anhydrous sodium sulfate
9. concentrationconcentrated
10. customThe resulting residue was purified by silica gel chromatography
11. washeluting with dichloromethane-n-hexane (1:3)

ORD record

ord-0322cceebe334cc599e829af5efea823

Source dataset

uspto-grants-1988_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04788320