Triacetoxyperiodinane → 9-Chloro-1-(4,6-dimethoxy-2-methylpyrimidin-5-yl)-1,2,3,4-tetrahydropyrimido[1,2-a]benzimidazole-6-carbaldehyde

Participants

Reaction Steps

To a stirred solution of methyl 9-chloro-1-(4,6-dimethoxy-2-methylpyrimidin-5-yl)-1,2,3,4-tetrahydropyrimido[1,2-a]benzimidazole-6-carboxylate (627 mg, 1.50 mmol) in tetrahydrofuran (15 mL) was added lithium borohydride (131 mg, 6.00 mmol) at room temperature. After being stirred for 15 h at ° C., the reaction mixture was quenched with aqueous ammonium chloride, extracted with ethyl acetate, and concentrated in vacuo. The resulting solid was washed with ethyl acetate and dissolved in dimethyl sulfoxide (15 mL). To the solution was added Dess-Martin reagent (1.27 g, 3.00 mmol) at room temperature, and the mixture was stirred for 15 h. The reaction mixture was diluted with ethyl acetate, quenched with aqueous sodium hydrogen carbonate, washed with water and brine, dried over sodium sulfate, filtered, and concentrated in vacuo. The residue was purified by flash column chromatography on silica gel eluting with a 20-80% ethyl acetate/hexane gradient mixture to give the title compound as a pale yellow solid (439 mg, 75%).

Provenance & Evidence