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