isosteres

Thioamides have been incorporated into peptides as isosteres for the amide bond.

Most CB antagonists reported so far are close analogs or isosteres of rimonabant.

Non-classical isosteres may be made up of similar atoms, but their structures do not follow an easily-definable set of rules.

According to Grimm, each vertical column (of Table below) would represent a group of isosteres.

Some examples of isosteres include:

Non-Classical Isosteres do not obey the above classifications, but they still produce similar biological effects in vivo.

Classical Isosteres are molecules or ions with the same number of atoms and/or the same number of valence electrons.

Classical isosteres are defined as being atoms, ions and molecules that had identical outer shells of electrons, This definition has now been broadened to include groups that produce compounds that can sometimes have similar biological activities.