Water → 3,3'-Bis(trifluoromethyl)benzophenone

Temperature

-78 °C

To a stirred solution of n-butyl lithium in hexane (1.6M; 100 mL) at -78° C. under argon, was added dropwise a solution of 3-bromobenzotrifluoride (36 g) in dry ether (75 mL) over 15 minutes. After the addition was complete, the solution was stirred at -78° C. for 45 minutes, then a solution of alpha,alpha,alpha-trifluoro-m-toluonitrile (25.7 g) in dry ether was added over 20 minutes. The deep red mixture was allowed to react at -78° C. for 30 minutes, then immediately after the cooling bath was removed 6N hydrochloric acid (100 mL) was added in a rapid stream. The reaction mixture decolorized and a dense precipitate formed as the reaction temperature rose rapidly to 0°-5° C. Water (200 mL) and ether (200 mL) were added, and the reaction was warmed to 35° C. and was stirred at that temperature until the precipitate dissolved (2 hours). After the reaction was cooled, the layers were separated and the aqueous phase was washed with ether (200 mL). The organic extracts were washed in turn with saturated sodium bicarbonate, then were combined, dried (MgSO4) and evaporated. The solid residue was dissolved in hot hexane (200 mL) and the mixture was left at 0°-5° C. overnight. The resulting colorless crystalline material was filtered, washed with hexane and dried to give 43.9 g of 3,3'-bis(trifluoromethyl)benzophenone mp 98.5°-99.5° C.

1. additionAfter the addition
2. customto react at -78° C. for 30 minutes
3. customimmediately after the cooling bath was removed 6N hydrochloric acid (100 mL)
4. additionwas added in a rapid stream
5. customa dense precipitate formed as the reaction temperature
6. customrose rapidly to 0°-5° C
7. temperaturethe reaction was warmed to 35° C.
8. stirringwas stirred at that temperature until the precipitate
9. dissolutiondissolved (2 hours)
10. temperatureAfter the reaction was cooled
11. customthe layers were separated
12. washthe aqueous phase was washed with ether (200 mL)
13. washThe organic extracts were washed in turn with saturated sodium bicarbonate
14. dry with materialdried (MgSO4)
15. customevaporated
16. dissolutionThe solid residue was dissolved in hot hexane (200 mL)
17. waitthe mixture was left at 0°-5° C. overnight
18. filtrationThe resulting colorless crystalline material was filtered
19. washwashed with hexane
20. customdried

ORD record

ord-c3d4597b8abb4c3b9e62d95cd12a09ac

Source dataset

uspto-grants-1988_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04788206