Features of the conformation of galunisertib molecules in the crystal structures of its solvates

Abstract

Crystal chemical analysis of 11 solvates of galunisertib (GAL·Q where GAL is C₂₂H₁₉N₅O, Q is a solvent molecule) – one of the most prolific compounds in the number of structurally characterized polymorphic modifications – was carried out using the method of molecular Voronoi–Dirichlet polyhedra. Based on the k–Φ criterion, it was established that all 12 crystallographically different GAL molecules in the 11 solvates realize unique conformations that have no analogues in the crystal structures of 10 pure GAL polymorphs containing also 12 different conformers. The same result was obtained on the basis of the simplified k–Φ criterion tested here for the first time, which takes into account Voronoi–Dirichlet polyhedra faces only with ranks equal to 2, 3, and 4. It was found that in all cases the difference in the conformations of GAL molecules is determined by a set of intramolecular contacts.