Imatinib (Gleevec@) conformations observed in single crystals, protein–Imatinib co-crystals and molecular dynamics: Implications for drug selectivity

N-(4-Methyl-3-((4-(pyridin-3-yl)pyrimidin-2-yl)amino)phenyl)-4-((4-methylpiperazin-1-yl)methyl)benzamide

Imatinib is one of the most used therapeutic agents to treat leukemia, which specifically inhibits the activity of tyrosine kinases. This polytopic molecule has been structurally characterized only in the form of its piperazin-1-ium salt (mesylate, picrate, citrate, fumarate or malonate). Herein we present the crystal structure of the freebase Imatinib which precipitated from a 1:10 mixture with arginine. The molecule realizes an extended conformation and forms infinite H-bonded chains through its amide, amine and pyrimidine groups.

Influence of noncovalent intramolecular and host–guest interactions on imatinib binding to MoS2 sheets: a PXRD/DFT study

The revealed pattern of imatinib drug binding to MoS2 sheets is promising for the combined exploitation of these species for therapeutic purposes.

Intermolecular Interactions in Crystal Structures of Imatinib-Containing Compounds

Imatinib, one of the most used therapeutic agents to treat leukemia, is an inhibitor that specifically blocks the activity of tyrosine kinases. The molecule of imatinib is flexible and contains several functional groups able to take part in H-bonding and hydrophobic interactions. Analysis of molecular conformations for this drug was carried out using density functional theory calculations of rotation potentials along single bonds and by analyzing crystal structures of imatinib-containing compounds taken from the Cambridge Structural Database and the Protein Data Bank. Rotation along the N-C bond in the region of the amide group was found to be the reason for two relatively stable molecular conformations, an extended and a folded one. The role of various types of intermolecular interactions in stabilization of the particular molecular conformation was studied in terms of (i) the likelihood of H-bond formation, and (ii) their contribution to the Voronoi molecular surface. It is shown that experimentally observed hydrogen bonds are in accord with the likelihood of their formation. The number of H-bonds in ligand-receptor complexes surpasses that in imatinib salts due to the large number of donors and acceptors of H-bonding within the binding pocket of tyrosine kinases. Contribution of hydrophilic intermolecular interactions to the Voronoi molecular surface is similar for both conformations, while π...π stacking is more typical for the folded conformation of imatinib.

Protonation effects on the UV/Vis absorption spectra of imatinib: a theoretical and experimental study

An experimental and theoretical investigation of protonation effects on the UV/Vis absorption spectra of imatinib showed systematic changes of absorption depending on the pH, and a new absorption band appeared below pH 2. These changes in the UV/Vis absorption spectra were interpreted using quantum chemical calculations. The geometry of various imatinib cations in the gas phase and in ethanol solution was optimized with the DFT/B3LYP method. The resultant geometries were compared to the experimentally determined crystal structures of imatinib salts. The semi-empirical ZINDO-CI method was employed to calculate the absorption lines and electronic transitions. Our study suggests that the formation of the extra near-UV absorption band resulted from an increase of imatinib trication concentration in the solution, while the rapid increase of the first absorption maximum could be attributed to both the formation of imatinib trication and tetracation.