Figure : Different reaction types for impurity prediction. Both impurity prediction and propagation for the products from step 1 have been shown in the schematic, and only the step impurities and the major product of step 2 are shown. The primary reactant for step 1 is denoted as a white triangle, with the primary product denoted as a blue triangle. The primary product of step 1 acts as the primary reactant for step 2, and results in the primary product of step 2 -red triangle. The legend denotes the additional reagents and solvents as squares, with the impurities in them, noted as green squares. The numbers within these squares are for the specific step they are a part of. Reagents and solvents for each step are on the reaction arrow, with the subscript denoting the specific step. The different shapes -rhombus, pentagon, and hexagon -are for the different impurities arising from reactions other than the major reaction for that particular step.