ERROR opening https://cactus.nci.nih.gov/chemical/structure/Nc2nc%28%3DO%29c1n%5BnH%5D%5BnH%5Dc1n2/file?format=sdf&get3d=True  -- Nc2nc%28%3DO%29c1n%5BnH%5D%5BnH%5Dc1n2 could not be loaded.