ERROR opening https://cactus.nci.nih.gov/chemical/structure/N%3DC1N%3DC%28O%29C%3D2NC%28CNC2N1%29C%28O%29C%28O%29C/file?format=sdf&get3d=True  -- N%3DC1N%3DC%28O%29C%3D2NC%28CNC2N1%29C%28O%29C%28O%29C could not be loaded.