General procedure: 4-methyl-5-hydroxyethyl thiazole (3.0 g, 21.0 mmol) was mixed with iodomethane (2.64 mL, 42.0 mmol) and heated to reflux for 2 hours. Upon completion of the reaction, excess iodomethane was removed by evaporation. Ether (50 mL) was added to the residual brown slurry and stirred for 30 minutes to promote crystallization. The precipitate was collected by filtration to afford 5-(2-hydroxyethyl)-3,4-dimethylthiazol-3-ium iodide (17) as a light yellow solid (5.76 g, 96.3% yield). The melting point of the product was 82-84 °C; 1H NMR (D2O, ppm): δ 4.14 (s, 3H, CH3N), 3.90 (t, 2H, CH2CH2O, J = 5.6 Hz), 3.19 (t, 2H, CH2CH2O, J = 6.0 Hz), 2.53 (s, 3H, CCH3).
