The purpose of a chemical structure search is to uncover chemical moieties that either exactly match or are similar to a chemical compound of interest. There are several different types of chemical structure searches that can be conducted, including:
Exact – A Chemical compound exactly matches the query compound.
Substructure – A chemical compound completely encompasses the query compound but may contain additional elements.
Markush – Chemical compounds being queried are potentially contained within a collection of generic or prophetic compounds defined using variable functional groups, atoms, ring sizes, etc.
Fragmentation – The Chemical compound is defined as the sum of its individual pieces or fragments and discovered compounds will contain the same collection of fragments but not necessarily connect in the same way that the query molecule was connected (i.e., functional groups, types of ring systems, etc.).
Chemical compounds may also be searched by molecular formula, CAS Registry Number ®, ring size and other chemical attributes. This type of search is often referred to as a dictionary search.