Synthesis, crystal structure and Hirshfeld surface analysis of 2-{4-[(2-chlorophenyl)methyl]-3-methyl-6-oxopyridazin-1-yl}-N-phenylacetamide

In the title molecule, C₂₀H₁₈ClN₃O₂, the 2-chlorophenyl group is disordered to a small extent [occupancies 0.875 (2)/0.125 (2)]. The phenylacetamide moiety is nearly planar due to a weak, intramolecular C—H...O hydrogen bond. In the crystal, N—H...O hydrogen bonds and π-stacking interactions between pyridazine and phenyl rings form helical chains of molecules in the b-axis direction, which are linked by C—H...O hydrogen bonds and C—H...π(ring) interactions. A Hirshfeld surface analysis was performed, which showed that H...H, C...H/H...C and O...H/H...O interactions to dominate the intermolecular contacts in the crystal.