Sodium Thiosulfate → 2-(4-(2,2-Dimethyl-1,3-dioxan-5-yl)methoxy-3,5-dimethylpyridin-2-yl)methylsulfinyl-1H-benzimidazole

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Reaction Steps

A toluene (4 ml) solution of 2-(((4-((2,2-dimethyl-1,3-dioxan-5-yl)methoxy)-3,5-dimethylpyridin-2-yl)methyl)thio)-1H-benzimidazole (500 mg, 1.21 mmol), zirconium(IV) isopropoxide isopropanol complex (295 mg, 0.76 mmol) and N,N,N′,N′-(−)-tetramethyl-(D)-tartaramide (396 mg, 1.94 mmol) was stirred in a nitrogen atmosphere at 40° C. for one hour. After the solution was cooled to room temperature, N,N-diisopropylethylamine (91 μl, 0.52 mmol) was added and subsequently, cumene hydroperoxide (243 μl, 1.32 mmol as the content was regarded as 80%) was added dropwise to the mixture and then the mixture was stirred at room temperature for 22 hours. After a saturated aqueous sodium hydrogen carbonate solution and a saturated aqueous sodium thiosulfate solution were added, the mixture was extracted with ethyl acetate. The organic layer was dried over anhydrous sodium sulfate, filtrated, and concentrated. The residue was purified by silica gel column chromatography (NH silica gel: 30 g, elution solvent: ethyl acetate, ethyl acetate/methanol 7:3, 1;1 gradient). The fractions containing the title compound were collected with ethyl acetate and concentrated to obtain the title compound (328 mg, yield: 63%) as a colorless foam.

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