Methanol → 2-[[(4-Methoxy-3,5-dimethyl-2-pyridinyl)methyl]sulfinyl]-1H-benzimidazole

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Reaction Steps

53.5 g of 2-[[(4-methoxy-3,5-dimethyl-2 -pyridyl)methyl]thio]benzimidazole are dissolved in 1.2 l of methylene chloride and 100 ml of methanol and then cooled to -20°. 33.4 g of m-chloroperbenzoic acid, recrystallized from methylene chloride/petroleum ether, are then introduced within 10 minutes. The solution is stirred for a further 60 minutes at -20° and then poured into a mixture of 250 ml of 2N sodium carbonate solution and ice. The organic phase is washed neutral with water, dried over sodium sulphate and evaporated in vacuo. Crystallization from methylene chloride/methanol/petroleum ether gives 2-[[(4-methoxy-3,5-dimethyl-2-pyridyl)methyl]sulphinyl]benzimidazole of melting point 157°-159°.

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