info:eu-repo/semantics/article
One-pot synthesis, quantum chemical calculations and X-ray diffraction studies of thiazolyl-coumarin hybrid compounds
Fecha
2018-06Registro en:
Saeed, Aamer; Arif, Mubeen; Erben, Mauricio Federico; Flörke, Ulrich; Simpson, Jim; One-pot synthesis, quantum chemical calculations and X-ray diffraction studies of thiazolyl-coumarin hybrid compounds; Pergamon-Elsevier Science Ltd; Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy; 198; 6-2018; 290-296
1386-1425
CONICET Digital
CONICET
Autor
Saeed, Aamer
Arif, Mubeen
Erben, Mauricio Federico
Flörke, Ulrich
Simpson, Jim
Resumen
Two closely related hybrid species containing both, thiazolyl and coumarin groups, were synthesized by using two different one-pot procedures from a common precursor. The reaction of α-bromoacetylcoumarin with thioacetamide in methanol furnished 3‑(2‑methylthiazol‑4‑yl)‑2H‑chromen‑2‑one (2), whereas refluxing α‑bromoacetylcoumarin with potassium thiocyanate in ethanol afforded 3‑(2‑ethoxythiazol‑4‑yl)‑2H‑chromen‑2‑one (3). Both derivatives were fully characterized by spectroscopic methods, elemental analysis and X-ray diffraction studies. Intramolecular C4?H⋯N and C5′?H⋯O[dbnd]C hydrogen bonds between the heterocycles determine the conformational behavior. The co-planarity of the coumarin and thiazolyl rings favors the occurrence of two remote orbital interactions involving the oxygen and nitrogen lone pairs and the corresponding σ*C?H electron acceptor, as demonstrated by Natural Bond Orbital population analysis. The 2-substitution of the thiazol‑4‑yl group has little effect on the molecular structures but causes significant differences in the crystal packing of the two compounds.