Building block is a term in chemistry which is used to describe a virtual molecular fragment or a real chemical compound the molecules of which possess reactive functional groups.
[8] Of special interest for this purpose are the building blocks common to known biologically active compounds, in particular, known drugs,[9] or natural products.
[10] There are algorithms for de novo design of molecular architectures by assembly of drug-derived virtual building blocks.
[14] Selection criteria applied to organic functionalized molecules to be included in the building block collections for medicinal chemistry are usually based on empirical rules aimed at drug-like properties of the final drug candidates.
[17] The building block approach to drug discovery changed the landscape of chemical industry which supports medicinal chemistry.