ERROR opening https://cactus.nci.nih.gov/chemical/structure/C%5BC%40H%5D1NC%28%3DNC%28%3DN1%29N%29N%28C%29C/file?format=sdf&get3d=True  -- C%5BC%40H%5D1NC%28%3DNC%28%3DN1%29N%29N%28C%29C could not be loaded.