Functional Groups as Binding Groups
Functional groups can play an important part in binding drugs to their targets, and structure–activity relationship studies can identify whether these groups are important or not. These studies can be carried out by preparing analogs from the lead compound itself. In order to determine whether a functional group is important, it is converted to another functional group. In order to test whether an alcohol or phenol is an important binding group, it can be converted to an ether or ester, then the analog is tested to see whether activity falls. Ketones and aldehydes contain carbonyl groups that are polarized so that the oxygen is slightly negative and the carbon is slightly positive. As a result, the functional group has a dipole moment that may have some role to play in drug-target interactions. Several drugs contain ester functional groups, which could interact with target binding sites as hydrogen bond acceptors.