Hydrochloric Acid → 2-Amino-3,4-difluorobenzoic acid

HRID 2257505Notes

Reaction equation

HRID 2257505 reaction equation
[F:1][C:2]1[C:10]([F:11])=[C:9]2[C:5]([C:6](=[O:13])C(=O)[NH:8]2)=[CH:4][CH:3]=1.[OH-:14].[Na+].OO.Cl>>[NH2:8][C:9]1[C:10]([F:11])=[C:2]([F:1])[CH:3]=[CH:4][C:5]=1[C:6]([OH:13])=[O:14]

Participants

5

Reactant 4

HCID 313Hydrochloric AcidHCID 784Hydrogen PeroxideHCID 14798Sodium HydroxideHCID 222743996,7-Difluoro-1H-indole-2,3-dione

Product 1

HCID 226211322-Amino-3,4-difluorobenzoic acid

Conditions

Temperature
65 °C

Procedure

6,7-Difluoroisatin (22.2 g) was added to a solution of sodium hydroxide (2N, 185 ml). Hydrogen peroxide (30%, 36 ml) was added at 40° C. or less over 20 minutes. After 1 hour the mixture was heated to 65° C. for 0.5 hours, cooled, poured onto water and acidified with concentrated hydrochloric acid. The resulting solid was filtered, washed with water and recrystallised from ethyl acetate/cyclohexane to give 2-amino-3,4-difluorobenzoic acid (11.3 g) as an orange solid, m.p. 207°-208° C.

Workup

  1. temperaturecooled
  2. additionpoured onto water
  3. filtrationThe resulting solid was filtered
  4. washwashed with water
  5. customrecrystallised from ethyl acetate/cyclohexane

Sources & evidence

ORD record
ord-f58cb40e2d0748a8bd2491c70a1e3d9e
Source dataset
uspto-grants-1997_08
Patent number
US05658858

Reaction notes

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