Ammonia → 2-amino-6-nitro-1H-benzoimidazole-4-carboxylic acid methyl ester

Participants

Reaction Conditions

Reaction Steps

1.0 g (5.2 mmol) of 2-amino-3H-benzoimidazole-4-carboxylic acid methyl ester was suspended in 10 mL of conc. H2SO4 at −15° C. and cooled to −30° C. Potassium nitrate (0.58 g, 5.72 mmol) dissolved in 10 mL of sulfuric acid and cooled to 0° C. was then added dropwise to the reaction mixture. The reaction mixture was stirred −30° C. for 15 min then warmed to −10° C. over 30 min. Then the mixture was poured into a beaker containing ice and neutralized (˜pH=8) with concentrated aqueous ammonia solution. The resulting solid was filtered. The solid obtained was washed with cold water and ether, and dried under vacuum to provide 0.85 g (70%) 2-amino-6-nitro-1H-benzoimidazole-4-carboxylic acid methyl ester as a solid. LCMS: 239 (M+1)+.

Provenance & Evidence