Acetic Anhydride → 1-[1-(4-Acetyl-2-chlorophenyl)-9-chloro-1,2,3,4-tetrahydropyrimido[1,2-a]benzimidazol-6-yl]propyl acetate

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Reaction Steps

To a solution of 1-{3-Chloro-4-[9-chloro-6-(1-hydroxypropyl)-3,4-dihydropyrimido[1,2-a]benzimidazol-1(2H)-yl]phenyl}ethanone (120.0 mg, 0.287 mmol) in pyridine (0.2 mL)/tetrahydrofuran (0.5 mL) was added acetic anhydride (0.5 mL) at 0° C. The reaction mixture was stirred at room temperature for 7 hrs. The mixture was concentrated. The residue was neutralized with aqueous saturated sodium hydrogen carbonate and extracted with ethyl acetate (×3). The combined organic layer was washed with brine (×1), dried over anhydrous magnesium sulfate, filtered and concentrated in vacuo. The residue was purified by silica gel column chromatography eluting with a 10-40% ethyl acetate/n-hexane gradient mixture. The residue was recrystallized from ethanol/n-hexane to give the title compound as a colorless powder (92.5 mg, 0.201 mmol, 70%).

Provenance & Evidence