ABSTRACT
Hydrogen bond donors (HDOs) and hydrogen bond acceptors (HACs)
• Ionic — Positive and negative centers • Nonpolar — Aromatic centers and hydrophobes
Pharmacophoric features are generalizations across atom types, so a HAC may be either a carbonyl oxygen or a pyridine-type nitrogen. Similarly, a HDO may be either a basic amino group or the OH group in an alcohol. They are, however, more fundamental than many of the functional groups commonly recognized in medicinal chemistry. Hence, an individual substructure can, and often does, present more than one feature, and the features presented may be of different types.
