Water → methyl N'-(chloromethylsulfonyl)carbamimidothioate

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Reaction Steps

Water (250 ml) is added with stirring to a slurry of S-methylisothiourea sulfate (77.3 g, 0.556 mol) and sodium carbonate (273 g, 2.58 mol) in methylene chloride (1100 ml). Chloromethanesulfonyl chloride (85% pure, 94.8 g, 0.542 mol) is then added slowly with stirring at such a rate as to maintain gentle reflux of the solvent. The mixture is then stirred at room temperature for 16 hr, and the organic solution is decanted from the inorganic residue. The residue is washed with additional methylene chloride (500 ml), and the combined organic solutions are dried with magnesium sulfate, filtered, and concentrated to leave crude II as a yellow oil (99.5 g, 90%). This crude material is adequate for preparing the thiadiazole compounds of the invention (e.g., see Example 4, below). Purification by chromatography on silica gel (2.5% ethyl ether in methylene chloride as eluant) provides the title compound as a colorless solid, mp 60°-62° C. (72 g, 65%).

Provenance & Evidence