反应详情

温度

-20 °C

tert-Butyl 2-methyl-4-trifluoromethoxyphenyl carbamate may be prepared in the following manner: 106 ml of a 1.5 M solution of tert-butyllithium in pentane are added dropwise over 1 hour to a solution, kept at −70° C. under an argon atmosphere, of 20 g of tert-butyl 4-trifluoromethoxyphenylcarbamate in 250 ml of anhydrous tetrahydrofuran. The mixture is stirred for 4 hours at −20° C., cooled to around −70° C., supplemented with 10.3 g of iodomethane and then stirred for 16 hours at a temperature close to 20° C. After hydrolysis with 100 ml of distilled water, the mixture is extracted with three times 60 ml of ethyl acetate. The combined organic extracts are dried over magnesium sulphate and concentrated to dryness under reduced pressure (2 kPa). The product obtained is suspended in petroleum ether, separated by filtration, washed with the same solvent and dried under reduced pressure (2 kPa). 15.1 g of tert-butyl 2-methyl-4-trifluoromethoxyphenylcarbamate are thus obtained in the form of a light orange-coloured solid melting at 98° C.

1. temperaturecooled to around −70° C.
2. stirringstirred for 16 hours at a temperature
3. customclose to 20° C
4. extractionthe mixture is extracted with three times 60 ml of ethyl acetate
5. dry with materialThe combined organic extracts are dried over magnesium sulphate
6. concentrationconcentrated to dryness under reduced pressure (2 kPa)
7. customThe product obtained
8. customseparated by filtration
9. washwashed with the same solvent
10. customdried under reduced pressure (2 kPa)