trans- and cis-2,5-Dimethoxy-3,6-diphenyl-3,6-dihydropyrazine

The title compounds, trans-C₁₈H₁₈N₂O₂, (I), and cis-C₁₈H₁₈N₂O₂, (II), both have an essentially planar central bis-lactim ether ring. Compound (I) is exactly centrosymmetric, with the trans-phenyl substituents nearly perpendicular to the ring [dihedral angle 86.0 (1)°]. In compound (II), the phenyl substituents lie on the same side of the ring, forming dihedral angles of 86.6 (1) and 72.3 (1)° with it in order to minimize repulsive interactions. The methoxy groups lie in the plane of the central ring in each case.

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