Sodium Hydroxide → 2-(2-{4-[1-(3-[1,3]dioxolan-2-yl-propyl)-1H-indol-3-yl]-piperidin-1-yl}-ethoxy)-benzoic Acid

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Reaction Steps

A solution of 2.75 g (7 mmol) of 2-{2-[4-(1H-indol-3-yl)-piperidin-1-yl]-ethoxy}-benzoic acid methyl ester (prepared as in Example 1, part D) in 10 mL of anhydrous DMF was added to a suspension of 0.36 g (9.1 mmol) of a NaH (60% dispersion in mineral oil) in 5 mL of anhydrous DMF under an inert atmosphere. After stirring for 30 minutes at room temperature, a solution of 1.1 mL (8.4 mmol) of 2-(3-chloro-propyl)-[1,3]dioxolane in 3 mL of DMF was added. The crude mixture was stirred at room temperature for 16 hours and the solvent was removed under reduced pressure. The residue obtained was dissolved with 150 mL of ethanol and 6 mL of a 2N NaOH aqueous solution were added. After 12 h at room temperature, the solvent was removed under reduced pressure. The crude mixture was dissolved with 50 mL of water and neutralised with a 2N HCl aqueous solution. The crude mixture was purified by flash chromatography over silica gel affording 0.83 g (29% of yield) of the expected product.

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