The standardised ChEMBL dataset was used to extract fragments. First, VQGAE was trained on this dataset and achieved a reconstruction rate of 94.5%. Fragment analysis was then performed on the same dataset. The environment around central atoms was used as two (i.e. only the alpha and beta atoms around the central atom were included). Several features of the atoms were kept in the fragment structures: presence of atom in the ring and maximum bond order around the atom.