3,4-Dichloro-2-methyl-5-ethoxycarbonylisothiazolium fluorosulfonate → 4-Chloro-5-ethoxycarbonyl-2-methyl-4-isothiazolin-3-one

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Reaction Steps

3,4-Dichloro-5-ethoxycarbonyl-2-methylisothiazolium fluorosulfonate (4.2 g, 0.012 mol) was added to 50 ml of saturated K2CO3 solution. The aqueous phase was extracted wih 3×50 ml of CH2Cl2. The combined extracts were dried (MgSO4), filtered and conc. to yield a solid. Recrystallization from heptane yielded 1.0 g (35%) of 4-chloro-5-ethoxycarbonyl-2-methyl-4-isothiazolin-3-one, mp 142-147. Analysis: Calculated for C7H8ClNO3S; C, 37.92; H, 3.65; Cl, 16.01; N, 6.31; S, 14.47. Found: C, 38.39; H, 3.81; Cl, 15.49; N, 6.31; S, 14.56.

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