ERROR opening https://cactus.nci.nih.gov/chemical/structure/OC1%3DC%28O%29C%28N%29%3DNC%28N%29%3DN1/file?format=sdf&get3d=True  -- OC1%3DC%28O%29C%28N%29%3DNC%28N%29%3DN1 could not be loaded.