ERROR opening https://cactus.nci.nih.gov/chemical/structure/O%3DC2N%28c1nc%28Cl%29nc1C%28%3DO%29N2C%29C/file?format=sdf&get3d=True  -- O%3DC2N%28c1nc%28Cl%29nc1C%28%3DO%29N2C%29C could not be loaded.