An orthorhombic polymorph of N,N′-bis(2-pyridylmethyl)pyrazine-2,3-dicarboxamide

The title compound, C18H16N6O2, can be crystallized in two polymorphic forms, viz. orthorhombic, described here, and triclinic. In the orthorhombic polymorph, both 2-pyridylmethyl moieties lie out of the plane of the pyrazine ring by ca 80degrees. One amide moiety lies in the plane of the pyrazine ring, while the other is almost perpendicular to the pyrazine ring. This structure contrasts with that of the triclinic polymorph, which is L-shaped, with one of the (2-pyridylmethyl)amide substituents lying almost in the plane of the pyrazine ring because of the presence of a bifurcated (N-H...N,N') intramolecular hydrogen bond.