ERROR opening https://cactus.nci.nih.gov/chemical/structure/COC1%3DCC2%3DC%28C%3DCN%3DC2C%3DC1%29/file?format=sdf&get3d=True  -- COC1%3DCC2%3DC%28C%3DCN%3DC2C%3DC1%29 could not be loaded.