Tetrafluoroboric acid → 3-Bromo-2-chloro-4,5-difluorobenzenediazonium tetrafluoroborate

Reaction equation

[Br:1][C:2]1[C:3]([Cl:11])=[C:4]([CH:6]=[C:7]([F:10])[C:8]=1[F:9])[NH2:5].[N:12]([O-])=O.[Na+].[F:16][B-:17]([F:20])([F:19])[F:18].[H+]>O>[F:16][B-:17]([F:20])([F:19])[F:18].[Br:1][C:2]1[C:3]([Cl:11])=[C:4]([N+:5]#[N:12])[CH:6]=[C:7]([F:10])[C:8]=1[F:9]

Participants

Procedure

To a suspension of 3-bromo-2-chloro-4,5-difluoroaniline (30.1 g) in 42% fluoroboric acid (180 ml) with stirring vigorously was added sodium nitrite (12 g) in water (30 ml) at -9° to 1° C. for 40 minutes. After stirred for 1.5 hours, the resulting precipitate was collected by filtration and washed with 42% fluoroboric acid and then with ether to give the title compound (35.6 g) as light yellow needles, mp>300° C.