Hydrochloric Acid → 1,2-Diamino-4,5-difluorobenzene

To a solution of 5.55 g (31.876 mmole) of 4,5-difluoro-2-nitroaniline in 50 mL of MeOH, were added 100 mL of 2N HCl and 8.90 g (159.380 mmole) of iron powder. The reaction mixture was stirred at room temperature for 2 hr and then filtered. The filtrate was neutralized with cone. NH4OH to ~pH 8. The resulting suspension was filtered again and the filter cake was washed thoroughly with MeOH. The filtrate and washings were combined, concentrated to ~100 mL and extracted with CHCl3 (100 mL×3). The CHCl3 solution was washed with a sat. NaCl solution (100 mL×2), dried (Na2SO4), and evaporated. The residue was coevaporated with CHCl3 to give 3.515 g (77%) of 10. This material was used in the next reaction without further purification. A brown crystalline sample of 10 was obtained by recrystallization from CCl4. 1H NMR DMSO-d6): d 6.44 (t, 2, 3-H and 6-H, JF-H =10.5 H), 4.59 (br. s, 4, 2×NH2).

1. filtrationfiltered
2. filtrationThe resulting suspension was filtered again
3. washthe filter cake was washed thoroughly with MeOH
4. concentrationconcentrated to ~100 mL
5. extractionextracted with CHCl3 (100 mL×3)
6. washThe CHCl3 solution was washed with a sat. NaCl solution (100 mL×2)
7. dry with materialdried (Na2SO4)
8. customevaporated

ORD record

ord-474cfdd0342e4940bee26e015720a046

Source dataset

uspto-grants-1998_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05712255