Hydrochloric Acid → 2-(4-Fluorophenyl)-5-valeroylpyridine

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Reaction Steps

A solution of 2-(4-fluorophenyl)-5-cyanopyridine (3.1 g) of Example 11 in tetrahydrofuran (30 ml) was added to a tetrahydrofuran solution (50 ml) of a Grignard reagent prepared from metallic Mg (0.6 g) and n-butyl iodide (4.4 g), followed by reacting the mixture at 60° C. for 5 hours, pouring the resulting solution in cooled 2N-HCl aqueous solution (100 ml), adding 2N-NaOH aqueous solution to make the solution alkaline, adding toluene (200 ml) to the solution, withdrawing the separated toluene layer, washing it with water till the washing water became neutral, distilling off toluene from the toluene layer and recrystallizing the residue from ethanol to obtain 2-(4-fluorophenyl)-5-valeroylpyridine (1.8 g) having a m.p. of 104.4° C. To this compound were added hydrazine hydrate (4 g), diethylene glycol (20 ml) and KOH (2.2 g), followed by agitating the mixture at 110° C. for one hour and further at 200° C. for 3 hours, cooling, adding chloroform (100 ml), washing the separated chloroform layer with water till the washing water became neutral, distilling off the solvent from the chloroform solution and distilling the residue to obtain the objective 2-(4-fluorophenyl)-5-n-pentylpyridine (0.3 g). B.P.: 152.0° C./2 mmHg. M.P.: 27.0° C.

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