Potassium hydroxy sulfite → 2-{[4-(Methylsulfinyl)-1,3-thiazol-2-yl]carbamoyl}phenyl acetate

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A solution of Oxone® (2.71 g, 4.44 mmol) dissolved in a minimum amount of water (15.0 mL) was added to a cold solution (0° C.) of 509 (0.514 g, 1.47 mmol) dissolved in a minimum amount of methanol (200 mL). On addition of the Oxone® solution a white solid precipitated. Additional methanol (100 mL) was added to the reaction. After stirring 25 min at 0° C., a saturated aqueous solution of Na2S2O3 was added to the reaction. The reaction was concentrated to remove excess methanol. The aqueous residue was washed four times with dichloromethane. The combined dichloromethane layers were washed with brine, dried over sodium sulfate and concentrated in vacuo to give crude 1 (0.66 g, >100%) as a white foam. This residue was dissolved in ethyl acetate and loaded onto a 90 g silica gel column that had been pre-equilibrated with ethyl acetate. The column was eluted with ethyl acetate. Like fractions of pure product were combined and concentrated in vacuo. The residue was stirred with ether and evaporated in vacuo to give 1 (0.288 g, 60%) as a white solid. 1H-NMR showed clean desired product contaminated with traces of residual dichloromethane and ethyl acetate. HPLC analysis indicated the product to be 95% pure (tR=5.01 min, Condition C) contaminated with 3% of 2 (tR=5.33 min, Condition C).

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