Synthesis and crystal structures of two novel triazolopyridine compounds solved by local L.S. minimizations from powder diffraction data

Abstract

The heteroaryl-substituted triazolopyridines 3-phenyl-7-(pyrazin-2-yl)-[1,2,3]triazolo[1,5-a]pyridine (2) and 3-[6-(pyridazin-3-yl)-pyridin-2-yl]-[1,2,3]triazolo[1,5-a]pyridine (4) have been synthesized and characterized (by HRMS, IR,1H and13C NMR, XRPD, melting point). The crystal structures have been solved from laboratory powder X-ray diffraction data with the direct-space strategy TALP for molecular compounds based on fast local least-squares minimizations. The crystal structure confirmed the formation of the tridentate compound4from a ring chain isomerization process. The almost planar arrangement of atoms in both the structures favors the presence of intermolecularπ–πinteractions, although weak C–H···N electrostatic interactions seem to be also important for the stabilization of the structure. Powder diffraction data have also proved to be sensible enough to determine the relative rotations of the six-membered rings despite the weak difference in scattering power between C and N atoms.