Yield:224048-17-3 98%

Reaction Conditions:

with sodium acetate in toluene;

Steps:

25 1-Cyclohexyl-3-ethyl-6-fluoro-1H-indazole

EXAMPLE 25 1-Cyclohexyl-3-ethyl-6-fluoro-1H-indazole To a solution of 1-(2,4-difluoro-phenyl)-propan-1-one (21.29 g, 125.1 mmol) in toluene (120 mL) was added sodium acetate (26.75 g, 326.1 mmol) and cyclohexyl/hydrazine mesylate (34.0 g, 163 mmol). The reaction mixture was heated to reflux in a Dean-Stark apparatus for 12 hours. The reaction was cooled to room temperature and poured into 1 N hydrochloric acid (100 mL). The toluene layer was separated and washed with water (75 mL) and brine (75 mL). The organic layer was dried over magnesium sulfate, filtered, and concentrated to yield 30.07 g of 1-cyclohexyl-3-ethyl-6-fluoro-1H-indazole (98% yield). ¹H NMR (400 MHz, CDCl₃) d 1.33 (t, 3, J=7.7), 1.35-1.44 (m, 2), 1.47-1.96 (m, 8), 2.93 (q, 2, J=7.7), 4.14-4.22 (m, 1), 6.81 (dt, 1, J=8.9, 2.1), 6.99 (dd, 1, J=9.8, 2.1), 7.40 (ddd, 1, J=8.7, 5.2, 0.4). ¹³C NMR (100 MHz, CDCl₃) d 13.97, 20.53, 25.37, 25.84, 32.32, 58.18, 94.77 (d, J=27.4), 109.11 (d, J=26.0), 119.38, 121.75 (d, J=11.5), 139.89 (d, J=13.0), 146.61, 161.95 (d, J=242). IR 2968, 2934, 2856, 1624, 1507, 1174, 1125, 825 cm^-1. Analysis calculated for C₁₅H₁₉FN₂: C, 73.14; H, 7.77; N, 11.37. Found: C, 73.33; H, 7.90; N, 11.46.

References:

US6211222,2001,B1