A three-dimensional hydrogen-bonded framework in 2-amino-6-(N-methyl­anilino)pyrimidin-4(3H)-one and a ribbon of fused hydrogen-bonded rings in 2-amino-6-(N-methyl­anilino)-5-nitro­pyrimidin-4(3H)-one

The mol­ecular dimensions of both 2-amino-6-(N-methyl­anilino)pyrimidin-4(3H)-one, C₁₁H₁₂N₄O, (I), and 2-amino-6-(N-methyl­anilino)-5-nitro­pyrimidin-4(3H)-one, C₁₁H₁₁N₅O₃, (II), are consistent with considerable polarization of the mol­ecular-electronic structures. The mol­ecules of (I) are linked into a three-dimensional framework by a combination of one N-H...N hydrogen bond, two independent N-H...O hydrogen bonds and one C-H...[pi](arene) hydrogen bond. The mol­ecules of (II) are linked into ribbons containing three types of edge-fused ring by the combination of two independent three-centre N-H...(O)₂ hydrogen bonds.

(E)-3-{2-Amino-4-eth­oxy-6-[N-(4-meth­oxy­phen­yl)-N-methyl­amino]pyrimidin-5-yl}-1-phenyl­prop-2-en-1-one: a boat-shaped pyrimidine ring and a chain of hydrogen-bonded R⁴₂(8) and R²₂(20) rings

In the title compound, C₂₃H₂₄N₄O₃, the pyrimidine ring adopts an almost perfect boat conformation, and the bond distances provide evidence for some polarization of the mol­ecular-electronic structure. Two independent N-H...O hydrogen bonds link the mol­ecules into chains of edge-fused R²₄(8) and R²₂(20) rings.