4-(Trifluoromethyl)phenyl isocyanate → 7-Pyridin-4-yl-6-{3-[3-(4-trifluoromethyl-phenyl)-ureido]-phenyl}-pyrazolo[5,1-b]thiazole-3-carboxylic acid ethyl ester

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Reaction Steps

6-(3-Amino-phenyl)-7-pyridin-4-yl-pyrazolo[5,1-b]thiazole-3-carboxylic acid ethyl ester (33 mg, 0.091 mmol) was dissolved in dry DCM (0.5 mL) under nitrogen atmosphere. p-Trifluoromethylphenylisocyanate (0.014 mL, 0.100 mmol, 1.1 eq) was added and the mixture was stirred at room temperature for 1 hour. The solution was evaporated to dryness and the crude product was purified by chromatography on silica gel (DCM/MeOH 97:3) to give 31 mg (61%) of 7-pyridin-4-yl-6-{3-[3-(4-trifluoromethyl-phenyl)-ureido]-phenyl}-pyrazolo[5,1-b]thiazole-3-carboxylic acid ethyl ester.

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