Aniline → 2-[(Methylsulfanyl)methyl]aniline

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Reaction Steps

Through this general procedure p-anisidine could be converted into 4-methoxy-2-(methylthiomethyl)aniline in 62 percent yield. The procedure is quite general. For a series of anilines (toluidine, aniline, p-chloroaniline, 4-nitroaniline, and p-ethoxycarbonylaniline) reaction of the aniline with the chlorine:sulfur compound complex chlorodimethylsulfonium chloride through the azasulfonium halide salt gave the corresponding 2-(methylthiomethyl)anilines in 54, 67, 45, 31 and 35% yields, respectively. The reaction is not restricted to chlorodialkylsulfonium chlorides. For example, when bromodimethylsulfonium bromide was used with aniline to form the azasulfonium bromide salt of aniline a 69 percent yield of 2-(methylthiomethyl)aniline was obtained. Treatment of aniline with halotetramethylenesulfonium halide (chloride or bromide) to form the azasulfonium salt followed by base treatment, gave 2-(2-tetrahydrothienyl)aniline in 20 percent yield. The use of β-keto sulfides and β-carboalkoxysulfides in this reaction provided a simple route to indoles and 2-oxindoles. Treatment of p-anisidine with chlorine:sulfur compound complex ##EQU11## to form the azasulfonium halide salt of the anisidine, followed by triethylamine, according to the above general procedure, gave 2-methyl-5-methoxy-3-methylthioindole in 38 percent yield. The reaction is not restricted to p-anisidine. With aniline, p-chloroaniline, and benzocaine, we obtained the corresponding unsubstituted, 5-chloro- and 5-ethoxycarbonyl-2-methyl-3-methylthioindoles in 68, 45 and 33 percent yields, respectively. Raney nickel desulfurization of the 3-methylthio compound gave 5-methoxy-2-methylindole in 72 percent yield.

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