3-DIFLUOROMETHYL-4,5,6,7-TETRAHYDRO-1H-INDAZOLE synthesis

Yield:938022-22-1 68%

Reaction Conditions:

with hydrazine in ethanol at 60; for 16 h;

Steps:

16

Description 16: 3-(difluoromethyl)-4, dro-1H-indazoleA mixture of 2-(difluoroacetyl)cyclohexanone (5.Og, 28.3mmol) and hydrazine monohydrate (1.93ml, 39.7mmol) in ethanol (100ml) was heated at 6O⁰C under argon for 16hr. The reaction mixture was cooled to room temperature, and the solvent evaporated off under reduced pressure. The resulting mixture was partitioned between ethyl acetate and brine. The organic layer was separated and washed with brine (4 x 30ml), then dried over sodium sulphate. The solvent was removed by rotary evaporation and the sample was recrystallised from ethyl acetate / n-pentane to give the title compound as a pale brown solid (3.305g, 68%).LC/MS (ES): Found 173 (ES+) retention time 2.34 mins. C₈H₁₀F₂N₂ requires 172. ¹ H-NMR (400MHz, DMSOd₆): 1.65 (4H, m), 2.44-2.60 (4H, m), 6.83 (1 H, t, J=54Hz), 12.71 (1 H, br s).

References:

WO2008/113795,2008,A1 Location in patent:Page/Page column 40