Pyridine → (Z)-1-[9-chloro-1-(2,4-dichlorophenyl)-3,4-dihydro-2H-pyrimido[1,2-a]benzimidazol-6-yl]-N-methoxypropan-1-imine

Participants

Reaction Conditions

Reaction Steps

A mixture of 1-[9-chloro-1-(2,4-dichlorophenyl)-1,2,3,4-tetrahydropyrimido[1,2-a]benzimidazol-6-yl]propan-1-one (630 mg, 1.54 mmol), O-methylhydroxylamine hydrochloride (386 mg, 4.62 mmol) and pyridine (3.9 mL) in ethanol (16 mL) was stirred at 80° C. for 26 hr. The mixture was concentrated in vacuo, diluted with saturated 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 20-40% ethyl acetate/n-hexane gradient mixture. The filtrate was concentrated in vacuo to give the solid, which was recrystallized from ethanol/ethyl acetate to give the title compounds as a colorless crystal respectively (E (Example 121): 266 mg, 0.608 mmol, 39%, Z (Example 122): 159 mg, 0.363 mmol, 24%).

Provenance & Evidence