The reaction of thieno[3,4-d]isothiazole-3(2H)-one-1,1-dioxide (I) with P2S5 in hot pyridine gives the corresponding thione (II), which by treatment with methyl iodide and NaOH to refluxing ethanol - water is converted to 3-(methylthio)thieno[3,4-d] isothiazole-1,1-dioxide (III). Finally, this compound is condensed with 2-[5-(dimethylaminomethyl)-2-furanylmethylthio]ethylamine (IV) to refluxing ethanol.

The reaction of thieno[3,4-d]isothiazole-3(2H)-one-1,1-dioxide (I) with P2S5 in hot pyridine gives the corresponding thione (II), which by treatment with methyl iodide and NaOH to refluxing ethanol - water is converted to 3-(methylthio)thieno[3,4-d] isothiazole-1,1-dioxide (III). Finally, this compound is condensed with 2-[5-(dimethylaminomethyl)-2-furanylmethylthio]ethylamine (IV) to refluxing ethanol.