反应详情

A hot solution of 3-amino-5-nitro-4-phenylbenzoic acid (39 g; prepared as in Example 1, step C) and potassium nitrite (15 g) in 1 N potassium hydroxide (260 ml) is added dropwise to a mixture of acetic acid (150 ml) and conc. hydrochloric acid (150 ml), while stirring vigorously at -2° to 2° C. After additional stirring at this temperature for about 10 minutes, 50% hydrofluoroboric acid (100 ml) is added during about 5 minutes, keeping the temperature below 5° C by external cooling. After additional stirring at about -10° C for 1 hour, the precipitated 5-carboxy-3-nitro-2-phenylbenzenediazonium tetrafluoroborate is collected by filtration, washed with icecold water (two portions of each 25 ml) and dried.

1. stirringAfter additional stirring at this temperature for about 10 minutes
2. customthe temperature below 5° C
3. stirringAfter additional stirring at about -10° C for 1 hour
4. filtrationthe precipitated 5-carboxy-3-nitro-2-phenylbenzenediazonium tetrafluoroborate is collected by filtration
5. washwashed with icecold water (two portions of each 25 ml) and
6. customdried