Sulfuric Acid → N-(1,3-dithiolan-2-ylidene)-4-[1-(methoxymethyl)propyl]aniline dihydrogen sulfate

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Reaction Steps

To a solution of 5.1 g of 4-[1-(methoxymethyl)propyl]aniline and 210 ml of dried dimethylformamide was added 7.25 g of triethylamine. Then, 8.8 g of methyl(1,3-dithiolan-2-ylidene)sulfonium iodide was added and the mixture was allowed to stir at room temperature for 3 hours. The mixture was then poured into water and the resulting aqueous mixture was extracted with 2:1 diethyl ether/ethyl acetate. The organic extract was washed with 0.2 N hydrochloric acid until all unreacted aniline had been removed as shown by thin-layer chromatography. The organic solution was then washed with water and aqueous saturated sodium chloride solution and dried over magnesium sulfate. The solvent was then removed to leave a crude yellow oil which was purified by flash chromatography using silica gel with ethyl acetate/hexane as eluant. The yellow oil obtained was N-(1,3-dithiolan-2-ylidene)-4-[1-(methoxymethyl)propyl]aniline and it was dissolved in 250 ml of diethyl ether. To this solution was added dropwise a solution of 2 g of sulfuric acid in 110 ml of diethyl ether. When the addition was complete, the resulting mixture was placed in a freezer. The solid which formed was separated by filtration and recrystallized from acetonitrile to give N-(1,3-dithiolan-2-ylidene)-4-[1-(methoxymethyl)propyl]aniline dihydrogen sulfate as small white crystals melting at about 134°-137.5° C.

Provenance & Evidence