Sodium Hydroxide → 4,6-dimethyl-5-methoxy-2-[[(3,4-dimethyl-2-pyridinyl)methyl]sulfinyl]-1H-benzimidazole

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Reaction Conditions

Reaction Steps

m-Chloroperbenzoic acid, 91% (0.53 g, 0.0028 mol) dissolved in CH2Cl2 (25 ml) and cooled to -10° C. was added under stirring to 4,6-dimethyl-5-methoxy-2-[[(3,4-dimethyl-2-pyridinyl)methyl]thio]-1H-benzimidazole (0.91 g, 0.0028 mol) dissolved in CH2CI2 (50 ml) maintaining the temperature at -5° C. Stirring was continued at -5° C. for 5 min and then NaOH (0.34 g, 0.0085 mol) dissolved in water (25 ml) was added under vigorous stirring. The two phases were separated and the aqueous phase was washed with CH2Cl2 (10 ml). More CH2Cl2 (50 ml) was added to the aqueous phase, the pH was adjusted to 9.5 by adding 2M HCl and after stirring the phases were separated. The organic phase was dried (Na2SO4), filtered and the solvent was evaporated off giving an oil which was crystallized from CH3CN (15 ml) yielding the desired product (0.3 g, 32%), m.p. 161° C.

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