The molecular structures extracted from ChEMBL as SMILES were imported into MOE (parsing failed for one molecule) and prepared using MOE's Wash function. Processing included the removal of the minor components of salts, neutralization, and the addition of hydrogen atoms. Any molecules with a molecular weight in the range of 150 to 1500 Da were kept. The molecules were then labeled "CSM" or "non-CSM" according to the following definition: CSMs are (i) macrocycles (i.e. molecules with at least one ring formed by at least 12 atoms) with 30 to 55 heavy atoms and (ii) non-macrocycles with 45 to 55 heavy atoms. Non-CSMs are nonmacrocycles with 15 to 30 heavy atoms. Compounds consisting of more than 55 heavy atoms were discarded (because of the excessive size of their conformational space), as were very small molecules (less than 15 heavy atoms) and CSMs with at least one undefined chiral atom (to ensure that stereochemistry is unambiguously defined for all queries).