[Br:1][C:2]1[N:6]([C:7]2[CH:12]=[CH:11][CH:10]=[CH:9][CH:8]=2)[N:5]=[C:4]([C:13]([O:15][CH2:16][CH3:17])=[O:14])[C:3]=1[CH:18]=[O:19].C1COCC1.[BH4-].[Na+]>CCO>[Br:1][C:2]1[N:6]([C:7]2[CH:12]=[CH:11][CH:10]=[CH:9][CH:8]=2)[N:5]=[C:4]([C:13]([O:15][CH2:16][CH3:17])=[O:14])[C:3]=1[CH2:18][OH:19]To an ice cooled solution of ethyl 5-bromo-4-formyl-1-phenyl-1H-pyrazole-3-carboxylate (3.82 g, 11.86 mmol, 1 eq) in a 1:1 mixture of THF: EtOH is added sodium borohydride (0.5 g, 13.04 mmol, 1.1 eq) portion wise. The reaction mixture is stirred at RT for 2 h. The reaction mixture is quenched with sat. NH4Cl solution and extracted with EtOAc. The organic layer is dried over Na2SO4 and concentrated. The crude is purified by column chromatography to afford 2.91 g (75%) of the title compound. 1H NMR (DMSO-d6, 400 MHz): δ 7.60-7.56 (m, 5H), 4.95 (t, J=5.4 Hz, 1H), 4.60-4.58 (d, J=5.4 Hz, 2H), 4.32 (q, J=7.01 Hz, 2H), 1.30 (t, J=7.7 Hz, 3H). HPLC (max plot) 96.75%; Rt 3.69 min
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