Stannous Chloride → 6-Bromo-3-phenyl-1H-indazole

Participants

Reaction Conditions

Reaction Steps

To a stirred mixture of (2-amino-4-bromophenyl)(phenyl)methanone (1.0 g, 3.6 mmol) in hydrochloric acid (6N aqueous solution, 5 mL) was added sodium nitrite (0.5 g, 7.2 mmol) over 3 min at 0° C. The mixture was stirred at 0° C. for 30 min before a solution of tin(II) chloride (2.7 g, 14.4 mmol in 5 mL concentrated hydrochloric acid) was added at 0° C. over 5 min. After stirring at 0° C. for 10 min and rt for 1 hr, the reaction mixture was filtered. The solid was washed with water (10 mL), 4N aqueous sodium hydroxide solution, and water (10 mL). The solid was dissolved in dichloromethane (20 mL), washed with brine (10 mL), dried (Na2SO4), and concentrated. Silica gel flash chromatography gave 6-bromo-3-phenyl-1H-indazole (0.42 g, 1.5 mmol, 42% yield).

Provenance & Evidence