ERROR opening https://cactus.nci.nih.gov/chemical/structure/O%3DC1%5CN%3DC2%5CN%3DC/NC2%3DC%28%5CN1%29N/file?format=sdf&get3d=True  -- O%3DC1%5CN%3DC2%5CN%3DC/NC2%3DC%28%5CN1%29N could not be loaded.