Sodium Hydroxide → 4-(4-Methyl-5-(methylsulfonyl)-4H-1,2,4-triazol-3-yl)pyridine

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Reaction Conditions

Reaction Steps

To a mechanically stirred solution of 4-[4-methyl-5-(methylthio)-4H-1,2,4-triazol-3-yl]pyridine (228 g) from the previous step, in a mixture of water (1.15 L) and acetic acid (1.15 L), was added portion-wise while cooling potassium permanganate (234 g), at such a rate as to maintain the temperature between 12 to 17° C. (ca. 45 min). The reaction mixture was then stirred at r.t. for 4 h before cooling on an ice-bath during the addition of a sodium hydroxide solution (5 N) over 2.5 h to set the pH to ca. 10. Dicalite® (100 g) and chloroform (1.6 L) was then added to the reaction mixture before filtration. The organic phase was separated from the filtrate and the aq. phase from the same was extracted with chloroform (2×1 L). The filter-cake was extracted twice with chloroform (2×1.5 L). The combined organic phases were dried over magnesium sulfate, filtered, and concentrated in vacuo to provide 158 g of the title compound as a white powder. Another crop (78 g, white powder) was obtained by extraction of the filter cake with chloroform (2×2 L) and concentration of this solution in vacuo. 1H NMR (DMSO-d6): 3.6 (s, 3H), 3.9 (s, 3H), 7.8 (s, 2H), 8.8 (s, 2H).

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