C[O:2][C:3]([C:5]1[N:6]=[CH:7][N:8]([C:10]([C:23]2[CH:28]=[CH:27][CH:26]=[CH:25][CH:24]=2)([C:17]2[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=2)[C:11]2[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=2)[CH:9]=1)=[O:4].[OH-].[Na+].Cl>CO.O.C(OCC)(=O)C>[C:10]([N:8]1[CH:9]=[C:5]([C:3]([OH:4])=[O:2])[N:6]=[CH:7]1)([C:17]1[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=1)([C:11]1[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=1)[C:23]1[CH:28]=[CH:27][CH:26]=[CH:25][CH:24]=1
A solution of 1-trityl-1H-imidazole-4-carboxylic acid methyl ester (1.75 g, 4.60 mmol) in methanol (50 mL) at 25° C. was treated with a 1N aqueous sodium hydroxide solution (13.8 mL, 13.8 mmol). The reaction was stirred at 25° C. for 18 h and then heated to 50° C. for 1.5 h. At this time, the reaction was cooled to 25° C. and diluted with water (150 mL). The aqueous layer was brought to pH=1 by treatment with a 1N aqueous hydrochloric acid solution and then diluted with ethyl acetate (250 mL). The resulting precipitated product was collected by filtration. The filtrate was extracted with ethyl acetate (1×150 mL). The combined organics were then washed with a saturated aqueous sodium chloride solution (1×100 mL), dried over magnesium sulfate, filtered, and concentrated in vacuo. The two batches of product were combined to afford 1-trityl-1H-imidazole-4-carboxylic acid (1.55 g, 95.1%.) as a white solid: LR-MS for C23H18N2O2 (M+H)+ at m/z=355.
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