Thionyl Chloride → 1-Piperidinyl(2-(4-pyridinylamino)phenyl)methanone

Beteiligte Stoffe

Reaktionsschritte

2-(4-Pyridinylamino)benzoic acid (244 g, 1.14 moles) was added with stirring at room temperature to 1.4 liters of thionyl chloride containing a catalytic amount (about 1.4 ml) of N,N-dimethylformamide. A mildly exothermic reaction ensued. The reaction was stirred at room temperature for 3 hours when the excess thionyl chloride was removed in vacuo. The residual oil was azeotroped twice with toluene. The yellowish gummy acid chloride was suspended in 1.5 liters of acetonitrile and 556 ml of piperidine was added with cooling (15°-20° C.) and stirring. Stirring was continued for 3 hours. The precipitated white solid was filtered and washed with a little cold acetonitrile. It was slurried once in about 2 liters of water while adjusting the pH to 9 by addition of potassium carbonate. The solid was dried and recrystallized from 2.7 liters of ethyl acetate to afford 166 g (51.6%) of 1-[2-(4-pyridinylamino)benzoyl]piperidine, m.p. 153°-156° C.

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