Pyridine → 5-bromo-6-isocyanato-3-methyl-1-(toluene-4-sulfonyl)-1H-indazole

Participants

Reaction Steps

5-Bromo-3-methyl-1-(toluene-4-sulfonyl)-1H-indazol-6-ylamine (138 mg, 0.36 mmol) was dissolved in 5 ml of toluene at room temperature. DMAP (1 eq, 44 mg), pyridine (1.3 eq, 0.04 ml) were added followed by phosgene (1.33 eq, 0.24 ml of a 20% solution in toluene). The mixture was allowed to stir at room temperature for 2 hours, forming a fine white precipitate. The mixture was filtered and the filtrate was concentrated in vacuo. The residue was diluted with dichloromethane and concentrated in vacuo again to give 5-bromo-6-isocyanato-3-methyl-1-(toluene-4-sulfonyl)-1H-indazole (150 mg, quantitative) as a white crystalline solid.

Provenance & Evidence