ERROR opening https://cactus.nci.nih.gov/chemical/structure/CC%28C%28C1CNC2%3DC%28N1%29C%28%3DO%29N%3DC%28N2%29N%29O%29O/file?format=sdf&get3d=True -- CC%28C%28C1CNC2%3DC%28N1%29C%28%3DO%29N%3DC%28N2%29N%29O%29O could not be loaded.