For this experiment, we focused on the synthesis route of an internal asset whose main compound has 41 non-hydrogen atoms, a molar weight of ca. 600 g/mol and is comprised of various functional groups, multiple annulated rings as well as a chiral spiro carbon. The synthesis route for this asset spans seven distinct steps involving four different starting materials and covering multiple reaction types like condensation, oxidation, or reductive amination reactions. We excluded from the template extraction procedure all reactions reported in the electronic laboratory notebook as making part of the test asset synthesis route, leaving us with 4,446 templates in total. Their application resulted in 20,813 simulated impurities with mass below 1,200 Da, and 154,756 corresponding simulated mass spectra. Of these impurities, 27 were also in our test dataset, which contained in total 61 impurities for this asset. In general, the chemical space covered by the simulated impurities included close matches for all experimental impurities (Figure ) and revealed additional impurity clusters that were not detected, possibly because the reaction conditions did not allow for such impurities to form in sufficient quantities, or they were not stable or isolated under the given work-up conditions. The same template can be applied to a variety of starting materials that present the required reactive sites. (c) We extracted over 4,000 reaction templates from our internal electronic lab notebook containing data for more than 2,000 reactions and 11,000 resulting impurities. (d) We simulated the synthesis route of an internal asset using the extracted reaction templates, excluding all templates extracted from reactions belonging to the test asset project.