ERROR opening https://cactus.nci.nih.gov/chemical/structure/C1%3DCC%3DC%28C%3DC1%29COCCCC2%3DCN%3DCN2/file?format=sdf&get3d=True  -- C1%3DCC%3DC%28C%3DC1%29COCCCC2%3DCN%3DCN2 could not be loaded.