7305-71-7

33342-65-3

(1) Preparation of 2-chloro-5-methylthiazole: 72 g (0.6 mol) of tert-butyronitrile was dissolved in 1.5 L of anhydrous acetonitrile to prepare a solution. Under nitrogen protection, 65 g (0.48 mol) of anhydrous copper (II) chloride was added to the reaction vessel. Under vigorous stirring and nitrogen atmosphere, the tert-butyl nitrile solution was slowly added to the reaction vessel. Subsequently, 45.6 g (0.40 mol) of 2-amino-5-methylthiazole was added in batches at 25 °C for about 40 min addition. The reaction mixture was continued to be stirred at 25°C for 2 hours. Upon completion of the reaction, the reaction was quenched by the addition of 20% hydrochloric acid solution. The solvent was removed by distillation under reduced pressure. To the residue, 300 mL of chloroform was added and the organic phase was washed with saturated saline (100 mL x 3). The organic layer was dried with anhydrous magnesium sulfate and the solvent was removed by distillation under reduced pressure to give 49.7 g of 2-chloro-5-methylthiazole in 93% yield.