Synthesis and crystal structure of 2-(2,4-dioxo-6-methylpyran-3-ylidene)-4-(4-hydroxyphenyl)-2,3,4,5-tetrahydro-1$H$-1,5-benzodiazepine

The title compound, C$_{21}$H$_{18}$N$_{2}$O$_{4}$, contains non-planar diazepine (in a boat–sofa conformation) and pyran (envelope) rings. In the crystal, O—H...O and N—H...O hydrogen bonds link the molecules, enclosing R $_{2}$ $^{2}$(16) and R $_{2}$ $^{2}$(24) ring motifs, to generate [110] chains. Very weak π–π stacking interactions between the phenyl rings of adjacent molecules with an inter-centroid distance of 4.0264 (9) Å help to consolidate a three-dimensional architecture. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H...H (45.1%), H...O/O...H (23.2%) and H...C/C...H (19.2%) interactions.