反应详情

2-Chloro-3-phenyl-4-methylsulfonylbenzoic acid (750 mg, 2.4 mmol), excess oxalyl chloride, and a few drops of N,N-dimethylformamide were dissolved in 1,2-dichloroethane and the mixture was allowed to react with stirring overnight. The mixture was then concentrated by evaporation under reduced pressure. The residue was taken up in about 10 mL of dichloromethane and the resulting solution was cooled with an ice bath. To this was added 410 mg (2.9 mmol) of 1-(1,1-dimethylethyl)-5-hydroxypyrazole and about 2 mL of triethylamine. After about 1 hour, the mixture was diluted with water and with more dichloromethane and the phases were separated. The organic phase was washed with dilute aqueous sodium bicarbonate, dried over sodium sulfate, and concentrated by evaporation under reduced pressure. The residue was dissolved in 10 mL of anhydrous 1,2-dimethoxyethane and 1.3 g (9.6 mmol) of sodium carbonate and then about 8 drops of acetone cyanohydrin were added. The mixture was allowed to react overnight and was then diluted with water. The phases were separated and the aqueous phase was extracted with ether, acidified with aqueous hydrochloric acid, and then twice extracted with dichloromethane. The dichloromethane extracts were combined and washed with saturated aqueous sodium chloride solution, dried over sodium sulfate, and concentrated by evaporation under reduced pressure. The 900 mg of residue was placed in 15 mL of ethanol and the mixture was heated and then cooled. The precipitate that formed was collected by filtration, washed with ether, and dried in a reduced pressure oven for 1 hour at 80° C. to obtain 682 mg (66 percent of theory) of the title compound as a tan solid melting at 262.5-264° C.

1. customto react
2. concentrationThe mixture was then concentrated by evaporation under reduced pressure
3. temperaturethe resulting solution was cooled with an ice bath
4. waitAfter about 1 hour
5. customthe phases were separated
6. washThe organic phase was washed with dilute aqueous sodium bicarbonate
7. dry with materialdried over sodium sulfate
8. concentrationconcentrated by evaporation under reduced pressure
9. dissolutionThe residue was dissolved in 10 mL of anhydrous 1,2-dimethoxyethane
10. customto react overnight
11. customThe phases were separated
12. extractionthe aqueous phase was extracted with ether
13. extractiontwice extracted with dichloromethane
14. washwashed with saturated aqueous sodium chloride solution
15. dry with materialdried over sodium sulfate
16. concentrationconcentrated by evaporation under reduced pressure
17. temperaturethe mixture was heated
18. temperaturecooled
19. customThe precipitate that formed
20. filtrationwas collected by filtration
21. washwashed with ether
22. customdried in a reduced pressure oven for 1 hour at 80° C.