Rank 2. Distance between 5 and 10 corresponds to the routes where disconnection strategy has differences with the observed routes, and in most of the cases that leads to the expected low feasibility of one or two key steps. These routes can, however, be corrected, and thus the retrosynthesis prediction be viewed as informative. A typical example of rank 2 is shown in Figure (molecule 34, distance 8.3). The suggested route is shorter than the experimentally observed (3 steps vs 4 steps). The disconnection strategy seems overall plausible. However, the last step N-alkylation can result in the mixture of regioisomers and thus require further optimization of conditions. Also, the use of dichloromethane as an alkylating agent should be replaced .