Synthesis of 1H-indazole
1627
Experimental section
Typical procedure for synthesis of ortho-substituted benzylidenehydrazine
Hydrazine (85%, 10 mL) was added into a solution of 2-fluorobenzonitrile (5 mmol)
in toluene (10 mL). Raney nickel (0.2 g) was added. Then, the mixture was stirred
for 3 h at 10–15 °C, giving 90% GC yield of 2-fluorobenzylidenehydrazine.
Typical procedure for cyclization of ortho-substituted benzylidenehydrazines
Hydrazine (85%, 5 mL) was added into the concentrated 2-fluorobenzylidenehy-
drazine solution (5 mmol). The mixture was refluxed for 5 h, giving 25% GC yield
of 1H-Indazole.
1
H-indazole (7)
1
H NMR (DMSO-d , 400 MHz, ppm): d = 7.11 (t, 1H, J = 7.6 Hz), 7.35 (t, 1H,
6
J = 7.6 Hz), 7.55 (d, 1H, J = 8.3 Hz), 7.79 (d, 1H, J = 8.2 Hz), 8.07 (s, 1H),
1
3
1
3.09 (s, 1H, NH); C NMR (DMSO-d , 100 MHz, ppm): d = 111.2, 121.0, 121.4,
6
1
22.5, 126.6, 135.2, 141.3.
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