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