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