Catalytic Reactions of Pyridines. V. Alkylation of α-, β-, and γ-Picolines with Alcohols catalyzed by Ammonium Halides

Abstract

A new method was found for the homogeneous liquid-phase alkylation of α-, β-, and γ-picolines with either methanol or ethanol. Addition of a catalytic amount of an ammonium halide to a mixture of a picoline and an alcohol resulted in a great increase in the yields of both side-chain-and α-alkylated derivatives of the starting picoline when the reaction was carried out at 320-335°C in an atmosphere of nitrogen. The higher the reaction temperature, the greater the yields of side-chain alkylated derivatives became. In practice, this alkylation gave 2-ethylpyridine and 2, 6-lutidine from α-picoline with methanol, 3-ethylpyridine and 2, 5-lutidine from β-picoline with methanol, 4-ethylpyridine and 2, 4-lutidine from γ-picoline with methanol, 2-propylpyridine and 2-ethyl-6-methyl-pyridine from α-picoline with ethanol, 2-ethyl-5-methylpyridine from β-picoline with ethanol, and 4-propylpyridine and 2-ethyl-4-methylpyridine from γ-picoline with ethanol.