New hybrid of the barbituric acid motif: synthesis, X-ray single crystal, DFT, and Hirshfeld surface analyses

A one-pot multi-component reaction of N,N-dimethylbarbituric acid,1,3-cyclohexanedione and 3-bromobenzaldehyde in H2O mediated by diethyl amine as a base affords a new barbituric acid–cyclohexanedione hybrid. The reaction proceeds smoothly, efficiently, and in high yield. The molecular structure of this compound was determined by single-crystal X-ray diffraction crystallography and spectrophotometric analyses. Of the nine possible isomers of the studied compound, the B3LYP/6-31G(d,p) method predicts that form B, in which the two OH groups are involved in significant intramolecular H-bonding interactions with the neighboring carbonyl O atom, is the most stable form in the gas phase. The X-ray structure reveals a different isomer due to intermolecular interactions caused by molecular packing in the crystal, which stabilizes the solid-state structure. Hirshfeld surface analysis of the molecular packing indicates that the H···O interactions are the primary contributor (24.5%) to the intermolecular stabilization in the crystal.