Yield:-

Reaction Conditions:

with bromine;acetic acid at 60 - 90; for 5.5 h;

Steps:

1

2,4-Dichlorothiazole (10 g, 64.9 mmol) was dissolved in acetic acid (50.0 ml) and heated to 60° C. Bromine (15.05 ml, 292 mmol) was added dropwise and the reaction mixture stirred at 90° C. for 5.5 hours. The mixture was cooled to room temperature and made basic by slow addition of solid sodium carbonate, then diluted with water (100 mL) and extracted with Et₂O (3×150 ml). The combined organic extracts were washed with sat. aq. sodium thiosulfate (50 ml) dried over sodium sulfate evaporated under reduced pressure to afford the title compound as a pale yellow oil. [1895] LC-MS Rt 1.43 min [M+H]⁺ 275.9/277.9/279.9/281.9 (Method 2minLowpHv03)

References:

US2014/171417,2014,A1 Location in patent:Paragraph 1894; 1895