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

Temperature

0 °C

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).

1. additionwas added at 0° C. over 5 min
2. filtrationthe reaction mixture was filtered
3. washThe solid was washed with water (10 mL), 4N aqueous sodium hydroxide solution, and water (10 mL)
4. dissolutionThe solid was dissolved in dichloromethane (20 mL)
5. washwashed with brine (10 mL)
6. dry with materialdried (Na2SO4)
7. concentrationconcentrated

ORD record

ord-aed51e37008c421ea37b24f2b8e5d42d

Source dataset

uspto-grants-2011_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08067447B2