Diiodomethane → 9-Chloro-6-[1-(cyclopropyloxy)-2,2,2-trifluoroethyl]-1-(2,4-dichlorophenyl)-1,2,3,4-tetrahydropyrimido[1,2-a]benzimidazole

Participants

Reaction Steps

A suspension of 1-[9-chloro-1-(2,4-dichlorophenyl)-1,2,3,4-tetrahydropyrimido[1,2-a]benzimidazol-6-yl]-2,2,2-trifluoroethanol (135 mg, 0.300 mmol), vinyl acetate (277 μL, 3.00 mmol), di-μ-chlorobis[(η-cycloocta-1,5-diene)iridium (I)] (50.4 mg, 0.0750 mmol) and sodium carbonate (19.1, mg, 0.180 mmol) in o-dichlorobenzene (3.0 mL) was stirred for 27 h at 100° C. The reaction mixture was purified by flash column chromatography on silica gel eluting with a 25% ethyl acetate/n-hexane. The obtained compound was dissolved in dichloromethane (1.6 mL). A solution of diethyl zinc in hexane (1.0 M, 818 μL, 0.818 mmol) and diiodomethane (132 μL, 1.64 mmol) was added at 0° C. After being stirred for 4 h at room temperature, the reaction mixture was diluted with ethyl acetate, quenched with aqueous ammonium chloride, washed with water and brine, dried over sodium sulfate, filtered, and concentrated in vacuo. The residue was purified by flash column chromatography on NH silica gel eluting with a 0-12% ethyl acetate/n-hexane gradient mixture to give the title compound as a colorless solid (62.9 mg, 0.110 mmol, 37%). Analytically pure material was obtained by recrystallization from ethyl acetate/hexane.

Provenance & Evidence