Methyl 3-(aminosulfonyl)-2-thiophenecarboxylate → 2H,3H-1lambda6-thieno[2,3-d][1,2]thiazole-1,1,3-trione

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Reaction Steps

32 g (0.145 mole) of methyl 3-sulfamoylthiophene-2-carboxylate (IX) in 145 ml of 1N methanolic sodium methylate solution is refluxed for 18 hours. The methanol is then evaporated off, the residue is taken up in water and a small amount of sodium bicarbonate, and the aqueous phase is extracted with methylene chloride and acidified with concentrated hydrochloric acid, whereupon the product precipitates as crystals which can be reprecipitated from water or ethanol.

Provenance & Evidence