反应详情

A mixture of 4-hydroxybenzaldehyde (60 g), sodium propionate (104 g) and propionic anhydride (190 ml) was stirred at 135°-140° C. for 40 hours. After the mixture was allowed to cool, water (600 ml) was added thereto, and stirred under ice cooling for 2-3 hours. The precipitate was collected by filtration, and washed well with water. Sodium hydroxide (60 g) was completely dissolved in water (800 ml) with stirring under ice cooling, and thereto was added the above-mentioned precipitate, and the mixture was stirred at the same temperature for 30 minutes. The insoluble materials were filtered off, and the filtrate was acidified with 5N hydrochloric acid under ice cooling. The resulting precipitate was collected by filtration, washed well with water to give 4-hydroxy-α-methylcinnamic acid (66 g). mp. 204°-205° C.

1. temperatureto cool
2. stirringstirred under ice cooling for 2-3 hours
3. filtrationThe precipitate was collected by filtration
4. washwashed well with water
5. dissolutionSodium hydroxide (60 g) was completely dissolved in water (800 ml)
6. stirringwith stirring under ice cooling
7. additionwas added the above-mentioned precipitate
8. stirringthe mixture was stirred at the same temperature for 30 minutes
9. filtrationThe insoluble materials were filtered off
10. filtrationThe resulting precipitate was collected by filtration
11. washwashed well with water