Sodium Carbonate → 2,2-Difluoro-6-[(4,5-dimethoxy-3-methyl-2-pyridinyl)methylsulfinyl]-5H-1,3-dioxolo[4,5-f]benzimidazole

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Reaction Steps

21 ml of a 0.1N solution of m-chloroperoxybenzoic acid in methylene chloride are added dropwise to a suspension, cooled to -40° C., of 0.80 g of 2,2-difluoro-6[(4,5-dimethoxy-3-methyl-2-pyridyl)methylthio]-5H-[1,3]-dioxolo[4,5-f]-benzimidazole in 10 ml of methylene chloride in the course of 10 minutes. The mixture is stirred for a further 20 minutes, during which the temperature is allowed to rise to -20° C., and 0.5 ml of triethylamine are added and the reaction mixture is poured into 40 ml of 5% strength sodium thiosulfate solution and 5% strength sodium carbonate solution. After phase separation, the aqueous phase is extracted twice more with 20 ml of methylene chloride each time; the combined organic phases are washed with a mixture of 5 ml of sodium thiosulfate solution and 5 ml of sodium carbonate solution, dried and concentrated. The residue is recrystallized from methylene chloride/diisopropyl ether. 0.62 g (75% of theory) of the title compound is obtained; decomp. 189°-190° C.

Provenance & Evidence