Hydrochloric Acid → 2-Cyanomethylbenzothiazole-6-sulfonic acid amide

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Reaction Steps

A suspension of 4-amino-3-mercaptobenzenesulfonamide (74 g, 208 mmol) and malononitrile (25 g, 375 mmol) in 650 mL of ethanol with 1.3 mL of conc. HCl was refluxed under argon overnight. The dark brown solids were isolated by filtration and were washed with ethanol and ether to yield approximately 30 g of the crude product. The volume of the filtrate was reduced by evaporation and the solids that precipitated were isolated by filtration to yield an additional 12 g of product. The crude material was purified by flash column chromatography eluting with CH2Cl2:MeOH:ammonia (60:20:1 mL) to yield a total of 22.2 g (35% for three steps) of the title compound as an orange powder.

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