ERROR opening https://cactus.nci.nih.gov/chemical/structure/CCCC%28CC1%3DCC2%3DCC%3DCC%3DC2C%3DC1%29NCCC/file?format=sdf&get3d=True  -- CCCC%28CC1%3DCC2%3DCC%3DCC%3DC2C%3DC1%29NCCC could not be loaded.