反应详情

To a mixture of 1-(trifluoromethyl)-4-vinylbenzene (2.0 g, 11.27 mmol), a compound of formula (20) and ethyl 2-chloro-2-(hydroxyamino)acetate (2.11 g, 13.52 mmol), a compound of formula (21), in anhydrous THF was added a solution of triethylamine (3.0 ml) in tetrahydrofuran was added dropwise at room temperature. The mixture was stirred overnight under N2. The white precipitate thus formed was filtered off, and washed twice with tetrahydrofuran (10 ml). The solvent was removed from the filtrate under reduced pressure, and the residue partitioned between water/ethyl acetate (20 ml:20 ml v/v), extracting three times with 20 ml of ethyl acetate. The combined organic layers were washed with aqueous ammonium chloride, and dried over MgSO4, to provide ethyl 5-[4-(trifluoromethyl)phenyl]-4,5-dihydroisoxazole-3-carboxylate, a compound of formula (22).

1. additionwas added dropwise at room temperature
2. customThe white precipitate thus formed
3. filtrationwas filtered off
4. washwashed twice with tetrahydrofuran (10 ml)
5. customThe solvent was removed from the filtrate under reduced pressure
6. customthe residue partitioned between water/ethyl acetate (20 ml:20 ml v/v)
7. extractionextracting three times with 20 ml of ethyl acetate
8. washThe combined organic layers were washed with aqueous ammonium chloride
9. dry with materialdried over MgSO4