Hydrazine hydrate (1:1) → 6-phenoxy-3-styryl-4,5-dihydro-1H-indazole

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of 3-phenoxy-6-(3-phenyl-acryloyl)-cyclohex-2-enone (1.13 g, 3.55 mmol) in 20 mL of HOAc/EtOH (1:1) was added hydrazine monohydrate (0.21 mL, 4.3 mmol). The reaction was heated at 70° C. for 3 h, cooled and poured cautiously into saturated NaHCO3 solution and extracted with EtOAc (2×). The combined organic layers were washed with saturated NaCl solution, dried (MgSO4) and concentrated under reduced pressure. The residue was chromatographed on silica gel eluting hexanes/EtOAc (2:1) to give 6-phenoxy-3-styryl-4,5-dihydro-1H-indazole (3) as an off-white solid (406 mg, 36%): 1H NMR (DMSO-d6) δ 2.64 (t, 2H, J=8.0 Hz), 2.95 (t, 2H, J=8.0 Hz), 5.46 (s,1H), 7.04 (AB, 2H, J=16.8 Hz), 7.15 (d, 2H, J=8.1 Hz), 7.25 (m, 2H), 7.42 (m, 4H), 7.55 (d, 2H, J=7.7 Hz), 12.44 (s, 1H). Anal. Calc. for C2H18N2O.0.2H2O: C, 79.32; H, 5.83, N, 8.81. Found: C, 79.36; H, 5.85; N, 8.84.

Provenance & Evidence