Fig. 2. (a) X-ray crystal structure showing the intramolecular phenol-amide H-bond when X = H and R = Me (CSD ref code KUSVUP). (b) Interaction of a H-bonded amide with a phosphine oxide. (c) Reference interaction of a non-H-bonded amide with a phosphine oxide. X is a substituent that modulates the H-bond donor properties of the phenol, and R is a solubilising group.
