That is, we hypothesized that the multiproduct and ambiguous reactions are artifacts, that could be, at least partially be responsible for query performance deterioration. For instance, we observed, that multiproduct reactions tend to involve products, that chemist would deem as byproducts. These simpler, more general substances are often reactant/reagent-like substances, thus we anticipated they can be accounted for many synthesis routes that are in fact artifacts. Imagine the scenario involving an organic reaction R 1 "producing" H 2 O (as a legit byproduct), and water being reactant/reagent in connection with another organic reaction R 2 , producing target molecule T . Clearly, water would not be considered as a valid intermediate in a synthesis route R 1 → R 2 leading to T.