Dimethylformamide → 6-(Trifluoromethyl)imidazo[2,1-b][1,3]thiazole-5-carboxylic acid

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Reaction Steps

At 0° C. POCl3 (17.1 mmol) is added dropwise to a solution of DMF (20.6 mmol) in chloroform (5.0 mL). A solution of 6-trifluoromethyl-imidazo[2,1-b]thiazole (3.17 mmol) in chloroform (15 mL) is added dropwise at 0° C. and the mixture is stirred for 3 h at RT. After heating for 2.5 d to reflux the mixture is poured into ice, extracted three times with DCM, dried over MgSO4 and concentrated under reduced pressure. DCM is added, the obtained precipitate is filtered off and the filtrate is concentrated in vacuo to give a crude product which is dissolved in tert.-butanol (19.5 mL). A solution of sodium chlorite (23.0 mmol) and sodium dihydrogen phosphate dihydrate (17.6 mmol) in water (19.5 mL) is added dropwise and the mixture is stirred for 90 min at RT. The solvents are partially removed in vacuo and the obtained precipitate is filtered off to give the desired product as a white solid. LC-MS: tR=0.73 min; [M+H]+=237.2.

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