Thionyl Chloride → 3-Chloromethyl-5,6-dimethoxy-1-(1-trityl-4-imidazolyl)methyl-1H-indazole

5,6-Dimethoxy-1(1-trityl-4-imidazolyl)methyl-1H -indazole-3-methanol (180.0 g), which had been ground in a mortar, was suspended in dichloromethane (1700 ml) at room temperature and then cooled with ice/water. Next, thionyl chloride (48.6 ml) was dropped thereinto within 5 minutes. The reaction mixture was poured into a saturated aqueous solution of sodium bicarbonate (2000 ml) and extracted with chloroform (5000 ml). After drying over sodium sulfate, filtering and evaporating under reduced pressure, a colorless solid was obtained (165.1 g). This solid product was used in the subsequent reaction without purification.