反应详情

A stirred solution of NaHMDS in THF (1.0 M, 3.1 mL, 3.1 mmol) was cooled in an ice water bath under Ar. 3-iodo-1H-pyrazole (500 mg, 2.6 mmol) was added as a solution in DMF (1 mL), washing with additional DMF (2×1 mL). 1,1-difluoro-2-iodoethane (0.47 mL, 5.2 mmol) was added in one portion and the mixture was removed from the cold bath. After 1.25 h, the reaction mixture was diluted with water and EtOAc. The phases were separated, and the organic phase was washed with water and brine, dried over Na2SO4, filtered and concentrated. The residue was purified by silica gel (0-15% EtOAc in hexanes) to provide 1-(2,2-difluoroethyl)-3-iodo-1H-pyrazole 7.02 (339 mg). Regiochemistry was assigned by NOE studies. LCMS-ESI+ (m/z): [M+H]+ calcd for C5H6F2IN2: 259.0; found: 258.2. 1H NMR (400 MHz, Chloroform-d) δ 7.29 (d, J=2.4 Hz, 1H), 6.46 (d, J=2.4 Hz, 1H), 6.06 (tt, J=55.4, 4.3 Hz, 1H), 4.45 (td, J=13.4, 4.3 Hz, 2H).

1. washwashing with additional DMF (2×1 mL)
2. customthe mixture was removed from the cold bath
3. additionthe reaction mixture was diluted with water and EtOAc
4. customThe phases were separated
5. washthe organic phase was washed with water and brine
6. dry with materialdried over Na2SO4
7. filtrationfiltered
8. concentrationconcentrated
9. customThe residue was purified by silica gel (0-15% EtOAc in hexanes)