We adapted the Chemformer model into different KD variants. The baseline Chemformer was originally pretrained on a masked auto-translation task on approximately 100 million randomly selected SMILES strings of molecules from the around 1.5 billion molecules in the ZINC-15 dataset . It was then fine-tuned on the USPTO-50k for the retrosynthesis task . We collected the corresponding dataset, original model weights and parameters from Irwin et al. . The USPTO-50k dataset contains around 50,000 reactions, and was here used to benchmark the model variants. Each Chemformer variant was trained on UPSTO-full, gathered from Genheden et al. . Both USPTO-50k and UPSTO-full originated from the USPTO dataset from Lowe . To evaluate the multi-step search, we used 5,000 ChEMBL structures from Genheden et al. . The stock was taken as the building block set of 24.7 million molecules from eMolecules .