A mixture of 1-[1-(2,4-dichlorophenyl)-2,3,4,5-tetrahydro-1H-[1,3]diazepino[1,2-a]benzimidazol-7-yl]propan-1-ol (160 mg, 0.409 mmol), tetra-n-propylammonium perruthenate (144 mg, 0.409 mmol), 4-methylmorpholine N-oxide (47.9 mg, 0.409 mmol) and dichloromethane (2.0 mL) was stirred at room temperature for 32 hr. The precipitate was removed by filtration, and the mother solution was diluted with aqueous sodium hydrogen carbonate and extracted with ethyl acetate. The combined organic layer was washed with brine, dried over anhydrous magnesium sulfate, filtered and concentrated in vacuo. The residue was purified by flash column chromatography on silica gel eluting with a 10-50% ethyl acetate/n-hexane gradient mixture. The filtrate was concentrated in vacuo to give the title compound as a colorless amorphous (11.0 mg, 0.0283 mmol, 7%).
