A reaction SMILES in the form "SMILES1>>SMILES2" (forward reaction) as well as "SMILES2>>SMILES1" (backward reaction) was generated for every selected molecular pair. The forward reaction SMILES was generated to always have the molecule with the lower heavy atom count as a reactant and the molecule with the higher heavy atom count as a product. The reaction SMILES for each drug pair was then encoded using DRFP. The 20 nearest neighbors (NNs) in the DRFP feature space were extracted and the minimum spanning tree layout calculated using the TMAP package. The resulting layout was displayed interactively using Faerun. In addition, the atom-mapping and the corresponding atom-mapping confidence scores were computed for each drug pair reaction SMILES using the published model described in the rxnmapper GitHub repository .