ERROR opening https://cactus.nci.nih.gov/chemical/structure/CCN%28CC%29CCC1%3DCNC2%3DC1C%3DCC%3DC2/file?format=sdf&get3d=True -- CCN%28CC%29CCC1%3DCNC2%3DC1C%3DCC%3DC2 could not be loaded.