CEQUINOR   05415
CENTRO DE QUIMICA INORGANICA "DR. PEDRO J. AYMONINO"
Unidad Ejecutora - UE
artículos
Título:
One-pot synthesis, quantum chemical calculations and X-ray diffraction studies of thiazolyl-coumarin hybrid compounds
Autor/es:
ARIF, MUBEEN; SAEED, AAMER; SIMPSON, JIM; FLÖRKE, ULRICH; ERBEN, MAURICIO F.
Revista:
SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY.
Editorial:
PERGAMON-ELSEVIER SCIENCE LTD
Referencias:
Año: 2018 vol. 198 p. 290 - 296
ISSN:
1386-1425
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.