Hydrogen Bromide → 2-Bromo-4-trifluoromethyl-thiazole-5-carboxylic acid ethyl ester

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Reaction Steps

To a solution of 2-amino-4-trifluoromethyl-thiazole-5-carboxylic acid ethyl ester (10 g) in 48% HBr (75 mL) at 0° C. is added a solution of sodium nitrite (4.25 g) in water (50 mL) dropwise over 1 h. The mixture is stirred at the same temperature for an additional 30 min, then a solution of CuBr (6 g) in 48% HBr (50 mL) is added dropwise over 30 min. The reaction mixture is stirred for additional 30 min at 0° C. and for 2 h at RT. The mixture is extracted three times with methylene chloride. The combined organic extracts are dried over magnesium sulfate and concentrated in vacuo. The residue is purified by chromatography (silica gel, hexane to 3% EtOAc/Hexane) to yield the title compound.

Provenance & Evidence