Observed and calculated 1H- and 13C-NMR chemical shifts of substituted 5H-pyrido[3,2-a]- and 5H-pyrido[2,3-a]phenoxazin-5-ones and of some 3H-phenoxazin-3-one derivatives.
Carbon and proton NMR spectra of several substituted 5H-pyrido[3,2-a]-, 5H-pyrido[2,3-a]phenoxazin-5-ones and 3H-phenoxazin-3-one derivatives have been assigned, and the experimental chemical shifts have been compared with the results of density functional calculations employing large basis sets. Solvent effects were explored by means of the polarizable continuum method (PCM), while the (limited) side-chain flexibility of the compounds has been addressed by Boltzmann averaging of the computed spectral parameters over different conformational minima. Overall, the calculated shifts reproduce well the experiment results; thus, the computational procedure represents a feasible and useful complement to multidimensional NMR experiments in the assignment process.
Crescenzi
Orlando
O
Department of Chemistry, University of Naples Federico II, Via Cintia, I-80126 Naples, Italy.
Correale
Gaetano
G
Bolognese
Adele
A
Piscopo
Vincenzo
V
Parrilli
Michelangelo
M
Barone
Vincenzo
V