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