ERROR opening https://cactus.nci.nih.gov/chemical/structure/c1%5BnH%5Dc2c%28n1%29%5BnH%5Dcnc2%3DO/file?format=sdf&get3d=True  -- c1%5BnH%5Dc2c%28n1%29%5BnH%5Dcnc2%3DO could not be loaded.