Preparation and Antihypoxic Activity of Complexes of Uracil Derivatives with Dicarboxylic Acids

Specific Intermolecular Interactions in the Supramolecular Structure of 5‐Hydroxy‐6‐Methyluracil: A DFT Study of the Hydrogen‐bonded Dimers

“…24 In the HMU dimers considered, the oxygen atoms of C O and O H groups play role of the bases, whereas the hydrogen atoms of the N H, O H, and CH 3 groups are acids. The total NBO energy of the hydrogen bonds, P E (2) , in the HMU dimers correlates with the dimerization enthalpy with the correlation coefficient R 2 = 0.971 (Figure 4). Only the dimer 4-4 falls out of the correlation.…”

“…Furthermore, the structure of the supramolecular ensembles depends on the nature of substituents in the 5‐ and 6‐positions of the pyrimidine ring. 5‐Hydroxy‐6‐methyluracil (HMU) has a wide range biological activity . The hydroxyl group of this compound allows the assembly of more ordered structures compared to other uracils.…”

“…5-Hydroxy-6-methyluracil (HMU) has a wide range biological activity. 2 The hydroxyl group of this compound allows the assembly of more ordered structures compared to other uracils. It is noteworthy that the supramolecular associates of HMU in the crystalline phase have the network structure with alternating hydrophilic (A) and hydrophobic (B) cavities ( Figure 1); between the layers, there is a specific stacking interaction.…”

“…At the same time, studying the process of selfassembly in solutions by experimental methods is a hard task, so the specific intermolecular contacts may be scrutinized by the quantum chemical methods. It is assumed that the self-assembly of HMU occurs via the intermediate formation of a dimer that contains O3 0 H•••O1 and N3 H•••O2 0 hydrogen bonds (dimer [2][3][4].…”

“…NBO energies E(2) of the hydrogen bonds in the HMU dimers and sign(λ 2 )ρ values in the critical points (3,-1) corresponding to the intermolecular hydrogen bond…”