1.
Magn Reson Chem
; 52(9): 491-9, 2014 Sep.
Artigo
em Inglês
| MEDLINE
| ID: mdl-25042582
RESUMO
Long-range coupling constants (5) JHortho,OMe were measured in series of methoxyindoles, methoxycoumarins, and methoxyflavones by the modified J doubling in the frequency domain method. The COSY and NOESY spectra revealed the coupling of the -OMe group with a specific proton at the ortho position and its preferred conformation. Homonuclear (1) H-(1) H couplings were confirmed by irradiation of the -OMe signal. Density functional theory calculations of (5) JHortho,OMe using the modified aug-cc-pVTZ basis set evidenced that the Fermi contact term shows good agreement with the experimental J values. Accurate chemical shift and coupling constant values followed after iterative quantum mechanical spectral analysis using the PERCH software.