ERROR opening https://cactus.nci.nih.gov/chemical/structure/n1c%28N%29nc%28N%29nc1N.N1C%28%3DO%29NC%28%3DO%29NC1%3DO/file?format=sdf&get3d=True -- n1c%28N%29nc%28N%29nc1N.N1C%28%3DO%29NC%28%3DO%29NC1%3DO could not be loaded.