Hydrochloric Acid → 7-Fluoro-5-methyl-2-(morpholin-4-ylcarbonyl)-6-phenyl-1,3-benzoxazole-4-carbonitrile

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Reaction Steps

Morpholine (269 μl, 3.08 mmol) was dissolved in dichloromethane (3 ml), and under nitrogen atmosphere at room temperature, trimethylaluminium (1.03 M hexane solution, 2.99 ml, 3.08 mmol) was added. After stirring at the same temperature for 15 minutes, a solution of ethyl 4-cyano-7-fluoro-5-methyl-6-phenyl-1,3-benzoxazole-2-carboxylate (I-111) (500 mg, 1.54 mmol) dissolved in dichloromethane (7 ml) was added at the same temperature. After stirring at the same temperature for 30 hours, an aqueous 1 M hydrochloric acid solution was gradually added at 0° C. The solution was extracted three times with dichloromethane. The organic layers were combined, washed with saturated brine, and dried over anhydrous sodium sulfate. The insoluble matter was separated by filtration, the solvent was evaporated away under reduced pressure, and the resulting residue was purified by middle-pressure liquid chromatography (eluent, hexane:ethyl acetate=3:2) to obtain the entitled compound (460 mg, 82%) as a white solid.

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