Reaction of 5-(3,4-dimethoxyphenyl)pyrazine-2,3-dicarbonitrile with alcohol in the presence of base

5-(3,4-Dimethoxyphenyl)pyrazine-2,3-dicarbonitrile reacts with methanol to give addition products, 3-methoxyiminopyrazine-2-carbonitrile and 2-methoxyiminopyrazine-3-carbonitrile derivatives, and/or substitution products, 3-methoxypyrazine-2-carbonitrile and 2-methoxypyrazine-3-carbonitrile derivatives. The selectivity between the addition and substitution depends on solvent polarity, base, and reaction time. The experimental results are accounted for by the equilibrium between the starting dinitrile and the addition products, methoxyiminopyrazine.