105827-91-6

White crystal or powder

2-Chloro-5-(chloromethyl)thiazole is a useful synthetic intermediate used in the synthesis of Ritonavir (R535000)

To a 2-liter round bottomed flask equipped with a mechanical stirrer, thermometer and a condenser, whose outlet was vented into an aqueous sodium hydroxide trap, was charged the crude mixture of cis- and trans-3-chloropropenyl isothiocyanates (504.2 g, 3.79 mol) and chloroform (600 mL). The mixture was stirred and heated to reflux. Chlorine (267.1 g, 3.77 mole) gas was bubbled under the surface of the reaction over a period of 6-8 h. The conversion of the isothiocyanates to 2-chloro-5- (chloromethyl)thiazole was monitored by GC. When the reaction was shown to be complete by GC analysis, the reaction mixture was cooled and then filtered. The filtrate was concentrated on the rotary evaporator to remove chloroform. Sodium bicarbonate (approximately 0.25 equivalents) was added to the concentrated filtrate, and the product 2-chloro-5-chloromethylthiazole was distilled at 97 °C under vacuum (6mm/Hg). The yield after distillation was 43%. 1 H NMR (CDCl3) δ: 7.3 (s, 1H); 4.6 (s, 2H). 13C NMR (CDCl3) δ: 152.6 (C-2); 140.2 (C-4); 137.5 (C-5); 37.1 (-CH2-).