ERROR opening https://cactus.nci.nih.gov/chemical/structure/O%3DC1/N%3DC%5CC%28%3DC%28%5CN%29N1%29C/file?format=sdf&get3d=True  -- O%3DC1/N%3DC%5CC%28%3DC%28%5CN%29N1%29C could not be loaded.