反应详情

To a solution of sodium ethanolate (prepared from 0.5 g of sodium) in dry ethanol (40 ml), ethyl 3-hydroxy-5-nitro-4-phenylbenzoate (4.4 g) is added followed by ethyl iodide (2.5 ml), and the resulting solution is refluxed for 20 hours. After about 6 hours an additional amount of sodium ethanolate (prepared from 0.25 g of sodiumn) in dry ethanol (10 ml) is added followed by ethyl iodide (1.3 ml). The mixture is evaporated in vacuo, 2 N sodium hydroxide (25 ml) is added to the residue, and the mixture is heated on a steam bath for 30 minutes to form a clear solution. On cooling, sodium 3-ethoxy-5-nitro-4-phenylbenzoate separates. It is collected by filtration, and washed with a small amount of icecold water. After drying, the sodium salt is dissolved in hot water (50 ml), and the 3-ethoxy-5-nitro-4-phenylbenzoic acid is precipitated by addition of 4 N hydrochloric acid (5 ml). After cooling, the acid is collected by filtration, washed with water and dried. After recrystallization from aqueous ethanol, it is obtained with a melting point of 174°-176° C.

1. temperaturethe resulting solution is refluxed for 20 hours
2. customThe mixture is evaporated in vacuo, 2 N sodium hydroxide (25 ml)
3. additionis added to the residue
4. temperaturethe mixture is heated on a steam bath for 30 minutes
5. customto form a clear solution
6. temperatureOn cooling
7. filtrationIt is collected by filtration
8. washwashed with a small amount of icecold water
9. customAfter drying
10. dissolutionthe sodium salt is dissolved in hot water (50 ml)
11. customthe 3-ethoxy-5-nitro-4-phenylbenzoic acid is precipitated by addition of 4 N hydrochloric acid (5 ml)
12. temperatureAfter cooling
13. filtrationthe acid is collected by filtration
14. washwashed with water
15. customdried
16. customAfter recrystallization from aqueous ethanol
17. customit is obtained with a melting point of 174°-176° C.