ERROR opening https://cactus.nci.nih.gov/chemical/structure/O%3DC%28NC%29c2ccc1cc%28ccc1c2%29C4%28O%29c3cncn3CC4/file?format=sdf&get3d=True  -- O%3DC%28NC%29c2ccc1cc%28ccc1c2%29C4%28O%29c3cncn3CC4 could not be loaded.