Molecular dynamics of 6-methyl-2-phenyl-2,3-dihydro-4H-chromen-4-one and 6-methyl-2-(4-nitrophenyl)-2,3-dihydro-4H-chromen-4-one (flavanone) derivatives in a solution studied by NMR spectroscopy

Molecular dynamics of benzoxazepin, oxime, pyrazole, and thiosemicarbazone derivatives of some flavanones have been investigated in a solution using NMR. The results confirm the formation of different O-H center dot center dot center dot O, O-H center dot center dot center dot N, N center dot center dot center dot H-N type intramolecular hydrogen bonds in the pyrazole and oxime molecules. The rotational barrier energy and energy of intramolecular hydrogen bonds have been determined. Copyright (C) 2013 John Wiley & Sons, Ltd.