反应详情

2,5,6-Trichloro-1H-benzoimidazole 2 (27.6 g, 0.125 mol) was dissolved in dry DMF (200 mL) and then K2CO3 (20.7 g, 0.15 mol) and dimethylsulfamoyl chloride (17.9 g, 0.125 mol) were added. The reaction mixture was stirred at room temperature for 16 hours. HPLC analysis showed the complete formation of 2,5,6-trichloro-benzoimidazole-1-sulfonic acid dimethylamide. In the same pot, without isolation of 2,5,6-trichloro-benzoimidazole-1-sulfonic acid dimethylamide, was added 1H-pyrazole-4-carboxylic acid ethyl ester (17.5 g, 0.125 mol) and K2CO3 (20.7 g, 0.15 mol). The reaction mixture was stirred at 70° C. for 4 hours and water (500 mL) was added while the reaction solution was still hot. The reaction solution was cooled to room temperature. The precipitated solid was collected via filtration, washed with water and dried. The crude product was used in the following reaction without further purification.

1. stirringThe reaction mixture was stirred at 70° C. for 4 hours
2. temperatureThe reaction solution was cooled to room temperature
3. filtrationThe precipitated solid was collected via filtration
4. washwashed with water
5. customdried
6. customThe crude product was used in the following reaction without further purification