5-Bromo-4-methyl-thiazol-2-amine

1603-91-4

3034-57-9

Step 1: Synthesis of 2-amino-5-bromo-4-methylthiazole A solution of bromine in chloroform (consisting of 66.7 mL (1.30 mol) of Br2 in 1000 mL of CHCl3) was slowly added dropwise to 120 g (1.05 mol) of 2-amino-4-methylthiazole dissolved in 2300 mL of CHCl3 while stirring continuously. Precipitation generation was observed during the dropwise addition. The reaction mixture was stirred continuously at room temperature for 48 hours. Upon completion of the reaction, the reaction mixture was filtered and the solid product was collected. The solid product was washed sequentially with dichloromethane and pentane to remove impurities. Subsequently, hydrobromide was dissolved in 2000 mL of water and the pH was adjusted to alkaline by adding 850 mL of 10% aqueous sodium bicarbonate. The aqueous phase was extracted with dichloromethane and the organic phases were combined and dried with anhydrous sodium sulfate. After removing the solvent by distillation under reduced pressure, a brown crystalline product was obtained. Yield: 155 g (crude yield: 76%). Melting point: 112-113 °C. 1H NMR (δ ppm, DMSO): 2.05 (s, 3H, CH3); 7.15 (s, 2H, NH2).