During the preprocessing of each original dataset parent molecular structures were gathered after a first standardisation using the ChEMBL structure pipeline . Then canonical tautomers were determined using the Pipeline Pilot tautomer enumerator with tautomerization of amides enabled. The canonical tautomers were then standardised once again with the ChEMBL structure pipeline after which the parent structures were obtained. Any molecule not parsable from simplified molecular input line entry specification (SMILES) by the RDKit 22 at any step of the previous workflow was considered failing the standardisation process.