To a stirred mixture of 1-naphthol (48.5 mg, 0.336 mmol), 1-[(2S,3R)-2-benzyloxy-5-hydroxy-3-pentyl]imidazole-4-carboxamide (85 mg, 0.280 mmol), and triphenylphosphine (88.2 mg, 0.336 mmol) in tetrahydrofuran (5 ml) was added dropwise diethyl azodicarboxylate (58.6 mg, 0.336 mmol) at ice-bath temperature. After the mixture was stirred overnight at room temperature, the solvent was removed in vacuo. The residue was purified by silica gel (10 g) chromatography eluting with chloroform/methanol (40:1) to give a mixture (60.6 mg) of 1-[(2S,3R)-2-benzyloxy-5-(1-naphthyloxy)-3-pentyl]imidazole-4-carboxamide (13) and by-products. This material was used without further purification.
