Methyl iodide → (SR)-2-((RS)-2,2-dimethyl-1,3-dioxolan-4-yl)-N-methyl-3-(methylthio)propan-1-amine

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Reaction Steps

To a solution of benzyl (SR)-2-((RS)-2,2-dimethyl-1,3-dioxolan-4-yl)-3-(methylthio)propylcarbamate (210 mg, 619 μmol) in dry THF (5 mL) was added sodium hydride 60% (34.6 mg, 866 μmol) and then methyl iodide (77 μl, 1237 μmol) and the mixture was stirred RT under argon for 30 mins. Chloroform was added followed by water. Normal processing afforded a syrup. Potassium hydroxide (1.0 g, 1.78E+04 μmol) was added to this material in isopropanol (8 mL) and the resulting solution was heated under reflux for 5 h. Silica gel was added, the mixture was concentrated to dryness and applied to a silica column. Elution with 5% MeOH/CH2Cl2 and then 7% 7N NH3/MeOH in CH2Cl2 gave (SR)-2-((RS)-2,2-dimethyl-1,3-dioxolan-4-yl)-N-methyl-3-(methylthio)propan-1-amine (105 mg, 479 μmol, 77% yield) as a syrup. 1H NMR δ 4.19 (1H, dd, J=6.7, 13.4 Hz); 4.06 (1H, dd, J=6.3, 8.1 Hz); 3.70 (1H, dd, J=7.3, 8.0 Hz); 2.76 (1H, dd, J=4.4, 13.1 Hz); 2.70-2.56 (3H, m); 2.42 (3H, s); 2.12 (3H, s); 1.97-1.87 (1H, m); 1.40 (3H, s); 1.34 (3H, s). 13C NMR (CDCl3) δ 109.0, 77.1, 68.0, 52.6, 42.2, 37.2, 34.5, 27.0, 25.7, 16.8.

Provenance & Evidence