ERROR opening https://cactus.nci.nih.gov/chemical/structure/N%28C%28NC%28NCCCCCC%2A%29%3DN%29%3DN%29%2A/file?format=sdf&get3d=True  -- N%28C%28NC%28NCCCCCC%2A%29%3DN%29%3DN%29%2A could not be loaded.