ERROR opening https://cactus.nci.nih.gov/chemical/structure/CCCN%28CC%29CCC1%3DCNC2%3DCC%3DCC%3DC12/file?format=sdf&get3d=True -- CCCN%28CC%29CCC1%3DCNC2%3DCC%3DCC%3DC12 could not be loaded.