Synthesis of 4-dimethoxymethyl-6-hydroxy-2-methoxynicotinonitrile: a suggested mechanism revision
Abstract
Methyl 4,4-dimethoxy-3-oxobutyrate (1) condenses with malonodinitrile (2) in methanolic sodium methoxide to form 4-dimethoxymethyl-2-methoxypyridine-3-carbonitrile (3a). A previously proposed interpretation of this reaction is shown to be only one of several which allow the formation of one isomer or another [6-alkoxy-2-hydroxy-(4) or 2-alkoxy-6-hydroxy-3-cyano-pyridines] depending on the pH of the medium.