Cysteamine Hydrochloride → NoName_3561

To a solution of p-methoxybenzaldehyde (1.81 g, 13.3 mmol) in ethanol (15 ml) was added dropwise a solution of cysteamine HCl (0.5 g, 4.4 mmol) in water (5 ml) and the solution stirred at RT for 18 h. The bulk of the ethanol was removed by rotary evaporator and the residue was diluted with water (15 ml) and extracted with diethyl ether (3×20 ml) to remove excess aldehyde. The aqueous layer was basified by addition of solid sodium carbonate (0.3 g) causing the product to precipitate out of solution. The precipitate was filtered, washed carefully with water (3×20 ml) and dried in a vacuum desiccator to give 2-(4-methoxyphenyl)-1,3-thiazolane (5) as a white solid (0.55 g, 69%), mp 94-95° (lit mp, 93-94°). 1H nmr (CDCl3, 300 MHz) 2.51, s, NH; 3.05-3.20, m, H4,4,5; 3.64, m, H5; 3.80, s, OMe; 5.23, s, H2; 6.87, d (8.7 Hz), H3′,5′; 7.44, d (8.7), H2′,H6′. ESI (+ve) MS m/z 196 (M+H, 100%).