To a solution of 7-[4-(2-butoxyethoxy)phenyl]-1-isobutyl-N-[4-[[(2-methoxy-3-pyridinyl)methyl]sulfanyl]phenyl]-2,3-dihydro-1-benzazepine-4-carboxamide (0.48 g) in methylene chloride (14.4 ml) was added dropwise a solution of m-chloroperbenzoic acid (187 g) in methylene chloride (9.6 ml) at −78° C., and the mixture was stirred for 15 minutes. To the reaction mixture was added an aqueous solution of saturated sodium thiosulfate. The mixture was extracted with ethyl acetate, and the organic layer was washed with saturated brine, and dried over magnesium sulfate. The solvent was removed under reduced pressure, and the obtained residue was purified by silica gel column chromatography, and recrystallized from ethanol, to give 7-[4-(2-butoxyethoxy)phenyl]-1-isobutyl-N-[4-[[(2-methoxy-3-pyridinyl)methyl]sulfinyl]phenyl]-2,3-dihydro-1-benzazepine-4-carboxamide (Compound 249) (267 mg).
