ERROR opening https://cactus.nci.nih.gov/chemical/structure/COC1%3DCC2%3DC%28C%3DC1%29C%28%3DCN2%29CCN/file?format=sdf&get3d=True  -- COC1%3DCC2%3DC%28C%3DC1%29C%28%3DCN2%29CCN could not be loaded.