ERROR opening https://cactus.nci.nih.gov/chemical/structure/CCC1%3DC%28C%28%3DC%28C%28%3DC1%29C%29N%29CC%29N/file?format=sdf&get3d=True  -- CCC1%3DC%28C%28%3DC%28C%28%3DC1%29C%29N%29CC%29N could not be loaded.