Building
blocks are the molecular foundations for drug molecule
design. The building block is one of the determining factors of final
compound qualities in any given medicinal chemistry campaign. Herein,
we describe our analysis of the building blocks used in parallel library
synthesis at AbbVie. The results gave insights into the synthetic
tractability and accessibilities of building blocks used in medicinal
chemistry. Furthermore, our analysis showed that opportunities still
exist for the identification and future incorporation of underrepresented
building blocks, even for commonly used reactions, to obtain intellectual
and competitive advantages in drug discovery.