Carbamic acid, ethyl ester → Ethyl difluoroacetylcarbamate

During a 30 minute period 65.4 g (0.55 mole) of thionyl chloride was added to 50.0 g (0.52 mole) of difluoroacetic acid while stirring. Gas evolved during the addition was returned to the reaction mixture by condensation on a dry ice condenser. After complete addition, the mixture was stirred at room temperature for approximately two hours. Urethane, 46.4 g (0.52 mole), was added and, after complete addition, the reaction mixture was heated at 60°-70° C. for three hours. The mixture was cooled to room temperature and stirred for approximately 18 hours. The mixture was heated at about 75° C. for two hours, then cooled. The mixture was evaporated under reduced pressure to leave an oily residue. This residue crystallized upon standing. The crystallized residue was washed with petroleum ether and filtered to yield 68.4 g of ethyl difluoroacetylcarbamate (mp 55°-57° C.).

1. additionGas evolved during the addition
2. customwas returned to the reaction mixture by condensation on a dry ice condenser
3. additionAfter complete addition
4. stirringthe mixture was stirred at room temperature for approximately two hours
5. additionafter complete addition
6. temperaturethe reaction mixture was heated at 60°-70° C. for three hours
7. stirringstirred for approximately 18 hours
8. temperatureThe mixture was heated at about 75° C. for two hours
9. temperaturecooled
10. customThe mixture was evaporated under reduced pressure
11. customto leave an oily residue
12. customThis residue crystallized
13. washThe crystallized residue was washed with petroleum ether
14. filtrationfiltered

ORD record

ord-fc10c7d6b56d4b0b8530e0a14eae40c9

Source dataset

uspto-grants-1989_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04806145