ERROR opening https://cactus.nci.nih.gov/chemical/structure/O%3DC1C%3DC2C%28O%29CN%28C%29C2%3DCC1%3DO/file?format=sdf&get3d=True  -- O%3DC1C%3DC2C%28O%29CN%28C%29C2%3DCC1%3DO could not be loaded.