ERROR opening https://cactus.nci.nih.gov/chemical/structure/O%3DC%28O%29C%28N%29Cc2c1ccccc1n%28c2%29C/file?format=sdf&get3d=True  -- O%3DC%28O%29C%28N%29Cc2c1ccccc1n%28c2%29C could not be loaded.