Hydrazine → HCID 11754688, compound

Participants

Reaction Steps

3-[5-(4-Bromo-phenyl)-1-β-tolyl-1H-pyrazol-3-yl]-2-m-tolyl-propionic acid ethyl ester. To a solution of 6-(4-bromo-phenyl)-6-oxo-2-m-tolyl-hex-4-ynoic acid ethyl ester (7.5 g, 19 mmol) in THF (40 mL) was added hydrazine (4.5 g, 28 mmol, 1.5 equiv) and Cs2CO3 (9.0 g, 28 mmol, 1.5 equiv). The reaction mixture was stirred at room temperature for 12 h. The resulting mixture was diluted with ethyl acetate (30 mL), and a satd aq solution of cesium carbonate (50 mL) was added. The resulting aqueous layer was back-extracted with ethyl acetate (2×30 mL). The combined organic layers were washed with satd aq NaHCO3 (50 mL) then brine (50 mL), and dried (MgSO4). The solvent was evaporated under reduced pressure, and the residue was purified by chromatography (silica gel, 25% ethyl acetate/hexanes) to afford the desired compound (5.5 g, 58%). TLC (silica gel, 3:7 EtOAc/hexanes): Rf=0.35. MS (ESI): mass calculated for C28H27BrN2O2, 502.13; m/z found, 503/505 [M+H]+. 1H NMR (400 MHz, CDCl3): 7.39 (d, J=10.7 Hz, 2H), 7.25-7.01 (m, 10H), 6.17 (s, 1H), 4.19-4.03 (m, 3H), 3.52 (dd, J=14.7, 9.6 Hz, 1H), 3.09 (dd, J=14.7, 6.0, 1H), 2.35 (s, 6H), 1.19 (t, J=7.1 Hz, 3H).

Provenance & Evidence