合成路线1

The acetylation of 3,5-dimethylaniline (I) with acetic anhydride gives the acetamide (II), which is treated with chlorosulfonic acid yielding the benzenesulfonyl chloride (III). The reduction of (III) with Na2SO3 and NaHCO3 in water affords the sulfinic acid (IV), which by reaction with sodium methoxide in methanol gives the corresponding sodium salt (V). The reaction of (V) with nitromethane and sodium methoxide yields the sulfonylnitromethane (VI), which is deacetylated with hot 2N NaOH affording 3,5-dimethyl-4-(nitromethylsulfonyl)aniline (VII). Finally, this compound is treated with thiophosgene in acetone to provide the target isothiocyanate.