ERROR opening https://cactus.nci.nih.gov/chemical/structure/N%28Nc1nn%5BnH%5Dn1%29c1nn%5BnH%5Dn1/file?format=sdf&get3d=True  -- N%28Nc1nn%5BnH%5Dn1%29c1nn%5BnH%5Dn1 could not be loaded.