ERROR opening https://cactus.nci.nih.gov/chemical/structure/O%3DC1NC%28%3DO%29NC%28%3DO%29C1%28C%28C%29C%29C%5CC%3DC/file?format=sdf&get3d=True -- O%3DC1NC%28%3DO%29NC%28%3DO%29C1%28C%28C%29C%29C%5CC%3DC could not be loaded.