反应详情

5-Carboxy-3-nitro-2phenylbenzenediazonium tetrafluoroborate (110 g ) is added in portions to a stirred and refluxing mixture of acetic anhydride (275 ml) and acetic acid (275 ml). The mixture is refluxed for a further 4-5 hours and is then poured into ice-water (about 4 liters). The mixture is left for 20 hours, and the precipitated crude 3-acetoxy-5-nitro-4-phenylbenzoic acid is collected by filtration, washed with water and dried. It is saponified by heating with 4 N sodium hydroxide (250 ml) for 30 minutes; the resulting solution is left at 5° C for about 20 hours and is then filtered. The filtrate is acidified with 4 N hydrochloric acid to precipitate 3-hydroxy-5-nitro-4-phenylbenzoic acid. It is collected by filtration, washed with water and dried. After recrystallization from aqueous methanol, the acid is obtained with a melting point of 213°-215° C.

1. temperaturerefluxing
2. temperatureThe mixture is refluxed for a further 4-5 hours
3. customthe precipitated crude 3-acetoxy-5-nitro-4-phenylbenzoic acid
4. filtrationis collected by filtration
5. washwashed with water
6. customdried
7. temperatureby heating with 4 N sodium hydroxide (250 ml) for 30 minutes
8. waitthe resulting solution is left at 5° C for about 20 hours
9. filtrationis then filtered
10. customto precipitate 3-hydroxy-5-nitro-4-phenylbenzoic acid
11. filtrationIt is collected by filtration
12. washwashed with water
13. customdried
14. customAfter recrystallization from aqueous methanol
15. customthe acid is obtained with a melting point of 213°-215° C.