2-Substituted perimidines: Zwitterionic tauterism in solid state, substituent effect on their crystal packing and biological activity

Structural and electronic properties of five 2-substituted 1H-perimidines: 3-(1H-perimidin-2-yl)propanoic acid (SPm), (Z)-3-(1H-perimidin-2-yl)acrylic acid) (MPm), (Z)-3-(1H-perimidin-2-yl)but-2-enoic acid (CPm-1), (Z)-2-methyl-3-(1H-perimidin-2-yl)acrylic acid (CPm-2) and 2-((1H-perimidin-2-yl)methyl)acrylic acid (IPm) have been studied. All perimidines bear aliphatic acidic substituents at 2-position andare distinguished by a carbon-carbon double bond in the substituents. The crystallographic X-ray diffraction analysis revealed that they exist in the solid state as zwitterions. Primary screening of 2-substituted 1H-perimidines against different cancer cell lines were also realized. The results obtained are discussed in terms of the structure-property relationships and compared with density functional theory calculations. Additionally, the effect of inclusion of water molecules in the crystal lattice on the molecular packing is analyzed. (C) 2021 Elsevier B.V. All rights reserved.