反应详情

To a stirred solution of 11.8 g (0.05 mole) of 2,4-dichloro-5-(1-methylethoxy)phenylhydrazine and 10.0 g (0.06 mole) of ethyl difluoroacetylcarbamate in 130 mL of xylene was added 2.5 g (0.02 mole) of phosphorus pentoxide. After complete addition the mixture was heated at reflux for 1.5 hours then allowed to cool to room temperature for approximately 18 hours. The reaction mixture was decanted from a dark residue in the reaction flask and washed with water. The washed mixture was extracted with a 10% aqueous sodium hydroxide solution. The basic extract was made acidic with concentrated hydrochloric acid to form an oily precipitate. This aqueous phase was decanted from the oily residue and fresh water added to wash the residue. This residue was dissolved in 160 mL of methylene chloride and filtered through a celite pad. The filtrate was dried over anhydrous magnesium sulfate and filtered. The filtrate was evaporated under reduced pressure to leave a semi-solid residue. The residue was triturated with approximately 125 mL of petroleum ether to provide 8.2 g of 1-[2,4-dichloro-5-(1-methylethoxy)phenyl]-3-difluoromethyl-4,5-dihydro-1,2,4-triazol-5(1H)-one.

1. additionAfter complete addition the mixture
2. temperaturewas heated
3. temperatureat reflux for 1.5 hours
4. customThe reaction mixture was decanted from a dark residue in the reaction flask
5. washwashed with water
6. extractionThe washed mixture was extracted with a 10% aqueous sodium hydroxide solution
7. extractionThe basic extract
8. customto form an oily precipitate
9. customThis aqueous phase was decanted from the oily residue and fresh water
10. additionadded
11. washto wash the residue
12. dissolutionThis residue was dissolved in 160 mL of methylene chloride
13. filtrationfiltered through a celite pad
14. dry with materialThe filtrate was dried over anhydrous magnesium sulfate
15. filtrationfiltered
16. customThe filtrate was evaporated under reduced pressure
17. customto leave a semi-solid residue
18. customThe residue was triturated with approximately 125 mL of petroleum ether