In the Journal of Organic Chemistry (JOC) article, Recent Changes in the Scaffold Diversity of Organic Chemistry As Seen in the CAS Registry, a large set of organic compounds extracted from the CAS Registry is analyzed to study recent changes in structural diversity. The diversity is characterized using the framework content of the compounds; the framework of a molecule is the scaffold consisting of all its ring systems and all the chain fragments connecting them. The compounds are partitioned based on their year of first report in the literature, which allows framework occurrence frequencies to be compared across a 10-year interval.

Results show the pace of innovation from a structural perspective is accelerating despite the extensive reuse of a relative small number of scaffolds.

CAS helps clients navigate the explored and unexplored regions of chemical space by leveraging its unique indexing of chemistry-related data at a molecular level to identify areas with limited activity as well as meaningful open areas of chemical space (i.e., scaffolds that are potentially important but have never been used as the basis for a molecule).