ERROR opening https://cactus.nci.nih.gov/chemical/structure/CCCC%28C%28%3DO%29C1%3DCC%3DCC%3DC1C%29N2CCCC2/file?format=sdf&get3d=True  -- CCCC%28C%28%3DO%29C1%3DCC%3DCC%3DC1C%29N2CCCC2 could not be loaded.