反应详情

温度

-78 °C

A solution of lithium diisopropylamide (16.5 ml of a 2 M solution in tetrahydrofuran/heptane/ethylbenzol, 33 mmol) in tetrahydrofuran (25 ml) was cooled to −78° C. Within 30 min a solution of ethyl acetate (3.77 ml, 38 mmol) in tetrahydrofuran (10 ml) was added. The solution was stirred for 45 min at −78° C., DMPU (6.63 ml, 55 mmol) was added within 20 min and the mixture was kept for additional 30 min at −78° C. Within 20 min a solution of 5-iodomethyl-1-methyl-3-(4-trifluoromethoxy-phenyl)-1H-pyrazole (4.2 g, 11 mmol) in tetrahydrofuran (25 ml) was added. The solution was stirred for 40 min at −78° C., the cooling bath was removed and stirring was continued for 1 h. The reaction mixture was poored onto aqueous NH4Cl solution/ice water and extracted two times with ethyl acetate. The combined extracts were washed three times with ice water/brine and dried over sodium sulfate. The solvent was removed under reduced pressure to give an orange oil which was purified by column chromatography (silica gel, heptane/AcOEt) to give 1.5 g (4.4 mmol, 40%) of the title compound as yellow oil.

1. waitthe mixture was kept for additional 30 min at −78° C
2. stirringThe solution was stirred for 40 min at −78° C.
3. customthe cooling bath was removed
4. stirringstirring
5. waitwas continued for 1 h
6. extractionextracted two times with ethyl acetate
7. washThe combined extracts were washed three times with ice water/brine
8. dry with materialdried over sodium sulfate
9. customThe solvent was removed under reduced pressure
10. customto give an orange oil which
11. customwas purified by column chromatography (silica gel, heptane/AcOEt)