反应详情

To an ice-cooled solution of 1,2-difluorobenzene (25 ml; 0.256 mol) in dry dichloromethane (170 ml), (S)-N-trifluoroacetylaspartic anhydride (12 g.; 0.054 mol) was added in one portion. To the resulting solution, anhydrous aluminium trichloride (21.5 g; 0.16 mol.) was slowly added portionwise, under vigorous stirring and dry nitrogen atmosphere, maintaining the temperature below 10° C. The so obtained deep-yellow suspension was stirred at room temperature for 3 hrs. and then at 50° C. for 5 hrs. The resulting reaction mixture was then poured into ice (400 g), and extracted with dichlorometane (3×100 ml), the collected organic extracts were washed with brine (2×50 ml ), dried (Na2SO4), and evaporated in vacuum to afford the crude product (7.3 g) as an oily material. Recrystallisation from hexane/ethyl ether afforded the pure titled compound as colourless prisms (8 g; 47%), m.p. 136°-137° C.

1. additionwas added in one portion
2. temperaturedry nitrogen atmosphere, maintaining the temperature below 10° C
3. customThe so obtained deep-yellow suspension
4. stirringwas stirred at room temperature for 3 hrs
5. customThe resulting reaction mixture
6. extractionextracted with dichlorometane (3×100 ml)
7. washthe collected organic extracts were washed with brine (2×50 ml )
8. dry with materialdried (Na2SO4)
9. customevaporated in vacuum
10. customto afford the crude product (7.3 g) as an oily material
11. customRecrystallisation from hexane/ethyl ether