Water → 6-Fluoro-3-(3-fluoro-4-pyridinylamino)benzo[b]thiophene

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A solution of 3-amino-6-fluorobenzo[b]thiophene (10 g, 60 mmol) and 4-chloro-3-fluoropyridine hydrochloride (12 g, 71 mmol) in 150 mL of 1-methyl-2-pyrrolidinone was stirred at 90-95° for 2.5 h, and thereafter cooled, stirred with water and extracted with ether. The aqueous layer was basified with 30% aqueous ammonium hydroxide and extracted with ether. The organic extract was washed with water and saturated sodium chloride solution, and dried (anhydrous magnesium sulfate), filtered and concentrated to give 13 g of a solid. Elution through silica with 10% ethyl acetate in dichloromethane via flash column chromatography yielded 7 g (44.6%) of a white solid, mp 155-157° C. Recrystallization of 2 g from acetonitrile afforded 1.3 g (29%) of white needles, mp 158-159° C.

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