[NH2:1][C:2]1[NH:6][N:5]=[C:4]([C:7]2[CH:12]=[CH:11][CH:10]=[CH:9][C:8]=2[Br:13])[CH:3]=1.C([N:22]=[C:23]=[S:24])(=O)C1C=CC=CC=1.[OH-].[Na+].[NH4+].[Cl-]>C1COCC1>[Br:13][C:8]1[CH:9]=[CH:10][CH:11]=[CH:12][C:7]=1[C:4]1[CH:3]=[C:2]([NH:1][C:23]([NH2:22])=[S:24])[NH:6][N:5]=1
To a solution of 5-amino-3-(2-bromophenyl)pyrazole (1.3 g, 5.46 mmol) in THF (20 mL) was added dropwise benzoyl isothiocyanate (0.81 mL, 6.0 mmol). The reaction mixture was stirred at room temperature for 3 hours, then 4 N aqueous solution of NaOH (4 mL) was added, and the reaction mixture was further stirred at 50° C. for 2 hours. The reaction mixture was cooled to room temperature, neutralized to pH 7 with a saturated solution of NH4Cl, and extracted with EtOAc (3×). The combined organic layers were directly purified on silica gel with 0-10% MeOH in CH2Cl2 as eluent to provide 1.62 g (quant.) of [5-(2-bromo-phenyl)-2H-pyrazol-3-yl]-thiourea as a yellowish foam. 1H-NMR (d6-DMSO) δ: 12.8 (broad s, 1H), 10.4 (broad s, 1H), 8.99 (broad s, 1H), 8.52 (broad s, 1H), 7.76 (d, 1H), 7.50 (m, 2H), 7.36 (t, 1H), 6.24 (broad s, 1H).
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