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

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Reaction Steps

A solution of 3-amino-6-fluorobenzo[b]thiophene (7 g) and 4-chloropyridine hydrochloride (7 g) in 200 mL 1-methyl-2-pyrrolidinone was stirred one hour at 80°-85° C. and thereafter cooled, stirred with water, basified with sodium carbonate and extracted with ethyl acetate. The organic extract was washed successively with water and a saturated sodium chloride solution and thereafter dried (anhydrous magnesium sulfate), filtered and concentrated to 10 g of a dark oil. This oil was eluted through silica with 10% methanol in dichloromethane via HPLC to yield 4.7 g of a brown solid, m.p. 102°-106° C. This was converted to the maleate salt in 20% methanol in ether and immediately thereafter recrystallized from 20% methanol in ether to yield 2.9 g of white crystals, m.p. 172°-174° (dec.).

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