ERROR opening https://cactus.nci.nih.gov/chemical/structure/O%3DC/1%5CC%28%3DC%29CC%28%3DC%5C1C%29%5CC/file?format=sdf&get3d=True  -- O%3DC/1%5CC%28%3DC%29CC%28%3DC%5C1C%29%5CC could not be loaded.