4-tert-Butoxycarbonylamino-1-methyl-1H-imidazole-2-carboxylic acid

24424-99-5

128293-62-9

128293-64-1

GENERAL STEPS: Ethyl 4-amino-1-methyl-1H-imidazole-2-carboxylate (0.38 g) and N,N-diisopropylethylamine (2 mL) were dissolved in N,N-dimethylformamide (8 mL) under dry conditions. Subsequently, di-tert-butyl dicarbonate (0.7 mL) was slowly added to this solution and the reaction mixture was stirred at 60 °C for 3 hours. Upon completion of the reaction, the mixture was cooled to room temperature and diluted by adding saturated sodium chloride solution (6 mL) and ether (6 mL). The organic layer was separated and washed sequentially with 10% aqueous citric acid solution, saturated sodium chloride solution, saturated sodium bicarbonate solution and saturated sodium chloride solution (10 mL each). The washed ether layer was dried with anhydrous sodium sulfate, filtered and concentrated under reduced pressure to remove the solvent. To the residue was added a methanol solution of 1 M sodium hydroxide (5 mL) and hydrolyzed with stirring at 60 °C for 1 hour. Upon completion of hydrolysis, the reaction mixture was cooled to 0 °C and the pH was adjusted to 2 with 1 M hydrochloric acid, at which point a white gel-like precipitate was formed. The precipitate was collected by gravity filtration, washed with water at pH=6 and subsequently freeze-dried to give 4-tert-butoxycarbonylamino-1-methyl-1H-imidazole-2-carboxylic acid as a white powder. Yield: 0.41 g, 76% yield.1H NMR (DMSO-d6) δ: 9.45 (broad single peak, 1H, NH), 7.21 (broad single peak, 1H), 3.86 (single peak, 3H), 3.67 (broad single peak, 1H, OH), 1.40 (single peak, 9H).