Synthesis, crystal structure and Hirshfeld surface analysis of 2-{4-[(2-chloro-phen-yl)meth-yl]-3-methyl-6-oxopyridazin-1-yl}-N-phenyl-acetamide.

In the title mol-ecule, C(20)H(18)ClN(3)O(2), the 2-chloro-phenyl group is disordered to a small extent [occupancies 0.875†(2)/0.125†(2)]. The phenyl-acetamide moiety is nearly planar due to a weak, intra-molecular C-H⋯O hydrogen bond. In the crystal, N-H⋯O hydrogen bonds and π-stacking inter-actions between pyridazine and phenyl rings form helical chains of mol-ecules in the b-axis direction, which are linked by C-H⋯O hydrogen bonds and C-H⋯π(ring) inter-actions. A Hirshfeld surface analysis was performed, which showed that H⋯H, C⋯H/H⋯C and O⋯H/H⋯O inter-actions to dominate the inter-molecular contacts in the crystal.