Synthesis, NMR, X-ray crystallography and DFT studies of some regioisomers possessing imidazole heterocycles

PÜSKÜLLÜ M. O., Doganc F., Ozden S., ŞAHİN E., ÇELİK İ., Goker H.

Journal of Molecular Structure, vol.1243, 2021 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 1243
  • Publication Date: 2021
  • Doi Number: 10.1016/j.molstruc.2021.130811
  • Journal Name: Journal of Molecular Structure
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Chemical Abstracts Core, INSPEC
  • Keywords: Imidazo[4,5-b]pyridine, Imidazo[4,5-d]pyrimidine, Regioisomer, NOESY, H-1-N-15 HMBC, DFT, HMBC NMR, DIFFERENTIATION, ELUCIDATION
  • Erciyes University Affiliated: Yes

Abstract

© 2021Imidazole-containing heterocycles: Imidazopyridines, imidazopyrimidines can exist in several tautomeric forms. Their regioselectivities were determined for N-alkylations with 4-chlorobenzyl bromide under basic conditions (K2CO3) in DMF. We observed that, regioisomers were mainly formed as a mixture in this reaction and N-benzylation occurs at a higher ratio on six membered heterocycles. Their structural assignments were made with the use of two-dimensional 1H–1H NOE (Nuclear Overhauser Effect Spectroscopy, NOESY) and 1H-15N HMBC (Heteronuclear Multiple Bond Correlation) spectra. Further confirmation of the structure of 2c and 3c were obtained from X-ray crystallography. Experimental data was confirmed by Density Functional Theory (DFT) studies as well.