Ammonium Chloride → 1-[5-(4-Fluoro-naphthalene-1-sulfonyl)2-methoxyphenyl] piperazine

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Reaction Steps

To a solution of 4-methoxy-3-[4-(2,2,2-trifluoro-acetyl)piperazin-1-yl]bezenesulfonyl chloride (0.19 g; 0.5 mmol), prepared as in Example 1 Step 2, in THF (0.5 mL) at ambient temperature under argon atmosphere was added dropwise a solution of 4-fluoro-1-naphthylmagnesium bromide in THF (0.25 M, 4 mL; 1 mmol). After stirring at this temperature for 1 h a saturated solution of ammonium chloride was added and the mixture was extracted into ethyl acetate (20 mL). The organic phase was dried (Na2SO4) and concentrated in vacuo .The residue was dissolved in dioxane (2 mL) and a solution of 6N NaOH (0.5 mL) was added. After stirring at ambient temperature for 1 h water was added (10 ml) and the mixture was extracted into ethyl acetate (20 ml). The organic phase was extracted into 2N aqueous HCl. The aqueous layer was adjusted with 6N NaOH solution to pH 14 and extracted with ethyl acetate. The organic phase was dried (Na2SO4) and concentrated in vacuo to give the 1-[5-(4-fluoro-naphthalene-1-sulfonyl)2-methoxyphenyl]piperazine (401) as a white solid (0.060 g; 30%). The hydrochloride salt was prepared from ethanol-hydrogen chloride, m. p. 155.0-159.0° C.

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