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

Participants

Reaction Conditions

Reaction Steps

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.

Provenance & Evidence