Hydrochloric Acid → 1-Trityl-1H-imidazole-4-carboxylic acid

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Reaction Steps

3H-Imidazole-4-carboxylic acid methyl ester (9.86 g, 78.2 mmol) is taken up in 150 mL DCM, triethylamine (11.9 mL, 86.0 mmol) is added and the reaction mixture is stirred for 5 min at RT. Chlorotriphenylmethane (24.0 g, 86.0 mmol) is added and the reaction mixture is stirred overnight at RT. The reaction mixture is extracted with an aqueous 5% NaHCO3 solution, the organic phase is dried over MgSO4 and concentrated under reduced pressure. The residue (20.7 g) is taken up in 100 mL MeOH, a solution of lithium hydroxide (4.80 g, 24.0 mmol) in 20 mL water is added drop wise and the reaction mixture is stirred over weekend at RT. The reaction mixture is acidified to pH 4 with 6N hydrochloric acid, 200 mL DCM is added and the two phase mixture is stirred vigorously. The phases are separated and the organic phase is dried over MgSO4 and concentrated under reduced pressure. Yield: 19.2 g. HPLC-MS: double peak tR=2.55/2.67 min, (M−H)−=353.

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