反应详情

An ozone stream (3 g ozone/hour) was conducted while stirring for 15 minutes through a solution, cooled to -70°, of 3 g of (RS)-2-(2-buten-1-yl)-4-thiochromanone in 100 ml of anhydrous dichloro-methane and 30 ml of anhydrous methanol. Subsequently, the solution was flushed with oxygen for 5 minutes and with argon for 10 minutes. After the addition of 2 ml of dimethyl sulfide, the mixture was stirred at room temperature for 16 hours. The reaction mixture was subsequently evaporated in a vacuum. The residue was treated with 50 ml of dichloromethane and, after the addition of 5 ml of water and 5 ml of trifluoroacetic acid, stirred at room temperature for 1 hour. The mixture was subsequently poured into 50 ml of water and neutralized by the spatula-wise addition of sodium hydrogen carbonate while stirring. An additional 50 ml of water were added, the phases were separated and the aqueous phase was extracted twice with 80 ml of dichloromethane each time. The combined organic phases were dried over magnesium sulfate and concentrated in a vacuum. There were obtained 2.8 g (99%) of 2-(2-oxoethyl)-4-thiochromanone as a yellow oil which was used in the next reaction without further recrystallization.

1. customSubsequently, the solution was flushed with oxygen for 5 minutes and with argon for 10 minutes
2. additionAfter the addition of 2 ml of dimethyl sulfide
3. stirringthe mixture was stirred at room temperature for 16 hours
4. customThe reaction mixture was subsequently evaporated in a vacuum
5. additionThe residue was treated with 50 ml of dichloromethane
6. additionafter the addition of 5 ml of water and 5 ml of trifluoroacetic acid
7. stirringstirred at room temperature for 1 hour
8. additionThe mixture was subsequently poured into 50 ml of water
9. additionneutralized by the spatula-wise addition of sodium hydrogen carbonate
10. stirringwhile stirring
11. additionAn additional 50 ml of water were added
12. customthe phases were separated
13. extractionthe aqueous phase was extracted twice with 80 ml of dichloromethane each time
14. dry with materialThe combined organic phases were dried over magnesium sulfate
15. concentrationconcentrated in a vacuum