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

HRID 724849Notes

Reaction equation

HRID 724849 reaction equation
[F:1][C:2]1[C:8]([F:9])=[CH:7][C:5]([NH2:6])=[C:4]([N+:10]([O-])=O)[CH:3]=1.Cl>CO.[Fe]>[F:1][C:2]1[C:8]([F:9])=[CH:7][C:5]([NH2:6])=[C:4]([NH2:10])[CH:3]=1

Participants

5

Reactant 2

HCID 313Hydrochloric AcidHCID 1571514,5-Difluoro-2-nitroaniline

Product 1

HCID 27367551,2-Diamino-4,5-difluorobenzeneYield 77%

Reagents, catalysts & solvents 2

HCID 23925IronCatalystHCID 887MethanolSolvent

Procedure

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 conc. NH40H 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).

Workup

  1. filtrationfiltered
  2. filtrationThe resulting suspension was filtered again
  3. washthe filter cake was washed thoroughly with MeOH
  4. concentrationconcentrated
  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

Sources & evidence

ORD record
ord-d28d8edbb0354264bb820ab2d1538128
Source dataset
uspto-grants-1998_01
Patent number
US05705490

Reaction notes

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