To a solution of methyl 2-hydroxymethyl-1 H-benzimidazole-4-carboxylate (1.0 g) in N,N-dimethylformamide (10 ml) were added tert-butylchlorodiphenylsilane (1.87 g) and imidazole (495 mg) at ambient temperature and the mixture was stirred at the same temperature for 28 hours. The reaction mixture was poured into water and the aqueous solution was extracted with ethyl acetate. The organic layer was washed with water and brine and dried over magnesium sulfate. The solvent was evaporated in vacuo and the residue was chromatographed on silica gel eluting with a mixture of n-hexane and ethyl acetate (10:1) to give methyl 2-tert-butyldiphenylsiloxymethyl-1 H-benzimidazole-4-carboxylate (1.45 g) as an oil.
