Ethanol → 2-Amino-5-(3-pyridylsulfinyl)thiazole

To a mixture of 2-amino-5-(3-pyridylthio)thiazole (3.0 g) in a mixture of dichloromethane (100 ml) and chloroform (100 ml) was added dropwise the solution of 3-chloroperbenzoic acid (3.4 g) in dichloromethane (50 ml) at 5° C. with stirring. The mixture was stirred at 5° C. for hours. The reaction mixture was washed with aqueous sodium bicarbonate and the aqueous layer was extracted with a mixture of tetrahydrofuran and ethyl acetate (1:1), washed with aqueous saturated sodium chloride and dried over magnesium sulfate. The solvent was concentrated under reduced pressure and the residue was recrystallized from ethanol no give 2-amino-5-(3-pyridylsulfinyl)thiazole (1.2 g, yield: 37.2%). mp: 178°-179° C. IR (Nujol): 3300, 3150, 1630, 1580, 1520, 1485, 1325, 1220 cm-1NMR (DMSO-d6, 200 MHZ, ppm): 7.58-7.70 (1H, m), 7.80 (1H, s), 8.00 (2H, s), 7.98-8.05 (1H, m), 8.72 (2H, br s) Mass: M+1 226, M 225, m/e 209, 177, 147