Fig. 1

Example of a molecule with different functional groups where non-unique group assignment is possible. The groups identified are marked by the dotted line. Depending on where the algorithm starts to assign the groups, the result of the fragmentation is different. If the molecule is fragmented starting from left to right, the result might be the one shown in a, while if it is fragmented from right to left, the result might be as shown in b. SMILES: C[NH]C(=O)OC