Synthesis, crystal structure and vibrational properties of N-(8-(3-(3-(tert-butyl)ureido)phenyl)imidazo[1,2-a]pyridin-6-yl)acetamide

Abstract

Derivatives of imidazo[1,2-a]pyridine, a type of fused heterocyclic substance, play major roles in the chemical fields and are confirmed to be the core fragments of various drug molecules. In this study, the title compound was designed and synthesized from the coupling reaction of N-(8-iodoimidazo[1,2-a]pyridin-6-yl)acetamide and 1-(tert-butyl)-3-(3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)urea. The crystals of the title compound were obtained by solvent evaporation at room temperature. The structure of N-(8-(3-(3-(tert-butyl)ureido)phenyl)imidazo[1,2-a]pyridin-6-yl)acetamide was demonstrated by 1H NMR, 13C NMR, FT-IR and single crystal X-ray diffraction studies. Additionally, theoretical calculations, based on the density functional method B3LYP at the 6-311+G(d, p) level, were performed on the title compound, and the molecular structure optimized using DFT was consistent with the results obtained using X-ray diffraction. In addition, hydrogen bonding, intramolecular π–π stacking and the Van der Waals forces significantly stabilized of N-(8-(3-(3-(tert-butyl)ureido)phenyl)imidazo[1,2-a]pyridin-6-yl)acetamide, as shown in the packing diagram. Moreover, the vibrations of the title compound were reliably assigned on the basis of characteristic vibrational absorption bands. Finally, frontier molecular orbital (FMO) was employed to verify the charge transfer interaction involving the electron acceptor and electron donor groups.