6-Bromo-3-fluoro-4-nitro-1-(phenylsulfonyl)-1H-indazole → 6-Bromo-3-fluoro-1-(phenylsulfonyl)-1H-indazol-4-amine

Participants

Reaction Steps

6-Bromo-3-fluoro-4-nitro-1-(phenylsulfonyl)-1H-indazole (5.9 g) was suspended in acetic acid (60 ml) and iron powder (4.12 g) was added. The suspension was heated to reflux. After 2 h the reaction mixture was diluted with ethyl acetate (100 ml) and filtered through celite. The filter cake was washed well with ethyl acetate then the filtrate basified to pH 8-9. The biphasic system was then stirred for ˜5 min. The layers were then separated, the aq washed with ethyl acetate and the combined organics washed with brine, dried (magnesium sulphate), filtered and concentrated in vacuum to yield a crude loaded onto a 330 g silica cartridge, purified on a 0-100% ethyl acetate:cyclohexane gradient and the relevant fractions combined and concentrated to yield the title compound, 2.4 g as a yellow solid.

Provenance & Evidence