ERROR opening https://cactus.nci.nih.gov/chemical/structure/O%3DC2Nc1c%28ccnc1N%28c3ncccc23%29C4CC4%29C/file?format=sdf&get3d=True  -- O%3DC2Nc1c%28ccnc1N%28c3ncccc23%29C4CC4%29C could not be loaded.