ERROR opening https://cactus.nci.nih.gov/chemical/structure/NC%28C%28%3DO%29C1%3DCC2%3DC%28C%3DC1%29OCO2%29C/file?format=sdf&get3d=True  -- NC%28C%28%3DO%29C1%3DCC2%3DC%28C%3DC1%29OCO2%29C could not be loaded.