ERROR opening https://cactus.nci.nih.gov/chemical/structure/Cn1cnc2c1c%28%3DO%29n%28c%28%3DO%29n2C%29C/file?format=sdf&get3d=True  -- Cn1cnc2c1c%28%3DO%29n%28c%28%3DO%29n2C%29C could not be loaded.