反应详情

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).

1. stirringthe reaction mixture was further stirred at 50° C. for 2 hours
2. temperatureThe reaction mixture was cooled to room temperature
3. extractionextracted with EtOAc (3×)
4. customThe combined organic layers were directly purified on silica gel with 0-10% MeOH in CH2Cl2 as eluent