Intra- and intermolecular hydrogen bonding in 3-hydroxy- and 5-hydroxychromone

The crystal structures for 3-hydroxychromone and 5-hydroxychromone have been obtained. Both molecules exhibit intramolecular hydrogen bonding between the hydroxy group and the ketone oxygen atom. However, only the 3-hydroxy derivative contains hydrogen bonds between molecules. By comparing the current results with those obtained for the corresponding flavone derivatives, the effect of the B phenyl group on hydrogen bonding is inferred.

Comparison of hydrogen bonding parameters between the title compounds and related flavones highlights the significance of the B phenyl ring for this interaction in 3-OH but not 5-OH derivatives.Figure optionsDownload as PowerPoint slide