Crystal structure and Hirshfeld surface analysis of ethyl 2-(7-chloro-3-methyl-2-oxo-1,2-di-hydro-quinoxalin-1-yl)acetate.

The quinoxaline moiety in the title mol-ecule, C13H13ClN2O3, is almost planar (r.m.s. deviation of the fitted atoms = 0.033 Å). In the crystal, C-H⋯O hydrogen bonds plus slipped π-stacking and C-H⋯π(ring) inter-actions generate chains of mol-ecules extending along the b-axis direction. The chains are connected by additional C-H⋯O hydrogen bonds. Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from H⋯H (37.6%), H⋯O/O⋯H (22.7%) and H⋯Cl/Cl⋯H (13.1%) inter-actions.

Synthesis, crystal structure and Hirshfeld surface analysis of (E)-benzo[d][1,3]dioxole-5-carbaldehyde oxime.

The asymmetric unit of the title mol-ecule, C8H7NO3, consists of two mol-ecules differing slightly in conformation and in their inter-molecular inter-actions in the solid. The dihedral angle between the benzene and dioxolane rings is 0.20 (7)° in one mol-ecule and 0.31 (7)° in the other. In the crystal, the two mol-ecules are linked into dimers through pairwise O-H⋯N hydrogen bonds, with these units being formed into stacks by two different sets of aromatic π-stacking inter-actions. The stacks are connected by C-H⋯O hydrogen bonds. A Hirshfeld surface analysis indicates that the most significant contacts in the crystal packing are H⋯O/O⋯H (36.7%), H⋯H (32.2%) and C⋯H/H⋯C (12.7%).