Hydrochloric Acid → 4-Cyano-7-fluoro-N,N,5-trimethyl-6-phenyl-1,3-benzoxazole-2-carboxamide

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Reaction Steps

Under nitrogen atmosphere, trimethylamine (1.03 M n-hexane solution, 2.25 ml, 2.31 mmol) was dropwise added at room temperature to a dichloromethane (3 ml) solution of dimethylamine hydrochloride (189 mg, 2.31 mmol), followed by stilling for 25 minutes. Subsequently, a dichloromethane (2 ml) solution of ethyl 4-cyano-7-fluoro-5-methyl-6-phenyl-1,3-benzoxazole-2-carboxylate (I-111) (250 mg, 771 μmol) was dropwise added, followed by stirring for 17 hours. After the reaction, aqueous 1N hydrochloric acid solution was added to the reaction liquid with cooling with ice, followed by stirring at room temperature, and the reaction liquid was extracted with chloroform. Next, the obtained organic layers were combined, dried oil anhydrous magnesium sulfate, filtered, and the filtrate was concentrated under reduced pressure. The resulting residue was suspended and washed in diethyl ether to obtain the entitled compound (167 mg, 67%) as a white solid.

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