ERROR opening https://cactus.nci.nih.gov/chemical/structure/O%3DC%28Nc1c2ncccc2ncc1%29Nc3ccc4nc%28oc4c3%29C/file?format=sdf&get3d=True -- O%3DC%28Nc1c2ncccc2ncc1%29Nc3ccc4nc%28oc4c3%29C could not be loaded.