[CH3:1][O:2][C:3]([C:5]1[N:6]=[CH:7][NH:8][CH:9]=1)=[O:4].C([O-])([O-])=O.[K+].[K+].[CH3:16][Si:17]([CH2:20][CH2:21][O:22][CH2:23]Cl)([CH3:19])[CH3:18].CN(C=O)C>CCOC(C)=O>[CH3:1][O:2][C:3]([C:5]1[N:6]=[CH:7][N:8]([CH2:23][O:22][CH2:21][CH2:20][Si:17]([CH3:19])([CH3:18])[CH3:16])[CH:9]=1)=[O:4]
A flask charged with 1H-imidazole-4-carboxylic acid methyl ester (0.29 g, 2.3 mmol), K2CO3 (0.60 g, 4.3 mmol), SEM-Cl (0.45 mL, 2.5 mmol) and DMF (5 mL) was heated for 12 h at 80° C. The reaction was diluted with EtOAc (20 mL) and washed with water (20 mL) and brine (20 mL) and the organic layer dried over MgSO4 and concentrated. The residue was purified by elution from a 20-g SPE cartridge (silica) with 5% MeOH/DCM to give 0.50 g (85%) of 1-(2-trimethylsilanyl-ethoxymethyl)-1H-imidazole-4-carboxylic acid methyl ester. This compound was stirred overnight at RT in MeOH (3.0 mL) and 1N NaOH (1.9 mL) and then concentrated to give 0.43 g (70%) of the title compound as a white solid. Mass spectrum (ESI), m/z): Calcd. for C10H18N2O3Si, 243.1 (M+H), found 243.1.
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