반응 #3155

반응 방정식

hydrochloric acid

bromine

sodium hydroxide

5-acetyl-2-methyl coumaran

hypobromous acid

→

5-carboxy-2-methylcoumaran

수율 57.4%

용매

water

dioxane

반응 조건

후처리

1. 1
   온도cooling
2. 2
   온도under cooling on an ice bath
3. 3
   기타The ice bath was removed
4. 4
   workup.ADDITIONafter the addition
5. 5
   workup.STIRRINGThe resultant mixture was stirred for 3.5 hours at room temperature
6. 6
   기타After the reaction
7. 7
   기타to precipitate a crystal
8. 8
   여과The crystal was recovered by filtration
9. 9
   세척washed with water
10. 10
    기타The resultant crystal was dried under reduced pressure
11. 11
    세척by washing with hexane and isopropyl ether successively

실험 절차

On an ice-common salt bath, 6.25 ml of bromine was added dropwise to a solution of 15.1 g of sodium hydroxide in 100 ml of water under stirring and cooling. To a solution of 6.50 g of 5-acetyl-2-methyl coumaran (Ml) in 100 ml of dioxane, the above mixture (i.e., hypobromous acid solution) was added dropwise at 3°-8° C. under cooling on an ice bath. The ice bath was removed after the addition. The resultant mixture was stirred for 3.5 hours at room temperature. After the reaction, the reaction mixture was poured into 500 ml of ice water, followed by addition of 30 ml of hydrochloric acid to precipitate a crystal. The crystal was recovered by filtration and washed with water. The resultant crystal was dried under reduced pressure, followed by washing with hexane and isopropyl ether successively to obtain 3.77 g of 5-carboxy-2-methylcoumaran (M2) (Yield: 57.4%).

출처