ERROR opening https://cactus.nci.nih.gov/chemical/structure/C1%3DC%28NC%3DN1%29/C%3DC%5CC%28%3DO%29O/file?format=sdf&get3d=True  -- C1%3DC%28NC%3DN1%29/C%3DC%5CC%28%3DO%29O could not be loaded.