Methyl triflate → 4-Acetylthiomethylthio-3-methyl-1,2,3-triazole

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Reaction Steps

To a solution of 4-acetylthiomethylthio-1,2,3-triazole (6 g : 31.75 mMol.) in tetrahydrofuran (30 ml) is added dropwise at -78° C. a solution of 1M lithium bis(trimethylsilyl)amide in tetrahydrofuran (35 ml : 35 mMol.), and the mixture is stirred at the same temperature for 5 minutes and added methyl trifluoromethanesulfonate (4.0 ml : 35 mMol.). After stirring at the same temperature for 2 hours, the reaction mixture is diluted with 10% hydrochloric acid (26 ml) and water, and extracted with ethyl acetate. The extract is washed with aqueous sodium hydrogen carbonate and brine, dried over sodium sulfate, and concentrated. The residue is purified by silica gel chromatography (n-hexane : ethyl acetate=1:2) to give 4-acetylthiomethylthio-3-methyl-1,2,3-triazole 2.22 g; NMR δ (CDCl3) ppm: 2.32(s, 3H). 4.13(s, 5H). 7.77(s, 1H).IR ν (CHCl3) cm-1 : 1698, 1429, 1355, 1263, 1226, 1205, 1127, 1100, 957. mp. 37°-38° C. Yield: 34%, 4-acetylthiomethylthio-1-methyl-1,2,3- triazole [884 mg; NMR δ (CDC13) ppm: 2.35(s, 3H), 4.11(s, 3H), 4.33(s, 2H), 7.59(s, 1H).IR (CHC13) cm-1 : 1691, 1434, 1354, 1285, 1131, 1106, 1048, 1031, 956.mp. 71°-72° C. Yield: 14%], and 4-acetylthiomethylthio-2-methyl-1,2,3-triazole [175 mg; NMR δ (CDC13) ppm: 2.35 (s, 3H), 4.20(s, 3H), 4.30(s,2H), 7.56(s, 1H).IR (CHCl3) cm-1 : 1691, 1446, 1369, 1130, 1006, 990, 956.Oil. Yield: 3%].

Provenance & Evidence