ERROR opening https://cactus.nci.nih.gov/chemical/structure/O%3DC1/C%3DC%28%5CC%3DC/C%3DC1/O%29C%28C%29C/file?format=sdf&get3d=True  -- O%3DC1/C%3DC%28%5CC%3DC/C%3DC1/O%29C%28C%29C could not be loaded.