The subset from the AstraZeneca ELN data accounts for 1.5 % of unique templates. Additionally, we observe that there is a greater overlap with Reaxys than the Patent data. These do not necessarily correspond to novel reactions, but rather are an artefact of the structural diversity present in the AstraZeneca collection. For instance, the synthesis of a novel lead compound could have different atomic environments around the reaction center compared to the literature or patent precedent on which it was based, thus leading to a new reaction template. Similarly, 2 % of all templates are common between the datasets, thus there is a small degree of structural overlap as might be expected.