Hydrochloric Acid → N-{1-[2-(3,4-dihydro-2H-1-benzopyran-4-yl)ethyl]-4-piperidyl}-4-fluorobenzamide hydrochloride

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Reaction Steps

The procedure is as in Example 4, but starting with 4-(2-bromoethyl)-3,4-dihydro-2H-benzopyran (1.9 g), N-(4-piperidyl)-4-fluorobenzamide hydrochloride (2 g), dry potassium carbonate (2.15 g) and potassium iodide (0.95 g) in 2-butanone (60 cc). The yellow oil obtained is purified by chromatography on a column 4 cm in diameter containing a silica gel (110 g), eluting with a toluene/diethylamine/ethanol mixture (60:20:20 by volume) (300 cc) and collecting 30-cc fractions. The fractions between 330 and 900 cc are concentrated to dryness. The yellow crystals obtained are dissolved in acetone (25 cc) and treated with a 3.4N solution (3 cc) of hydrochloric acid in isopropanol. The precipitate formed is filtered off on sintered glass and then recrystallized in an ethanol/acetone mixture (20:60 by volume) (80 cc). After the addition of ethyl ether (10 cc), N-{1-[2-(3,4-dihydro-2H-1-benzopyran-4-yl)ethyl]-4-piperidyl}-4-fluorobenzamide hydrochloride (2.05 g) is obtained in the form of a crystalline white solid, m.p. 240° C.

Provenance & Evidence