ERROR opening https://cactus.nci.nih.gov/chemical/structure/O%3DC2/N%3DC%28%5CNc1n%28cnc12%29COC%28CO%29CO%29N/file?format=sdf&get3d=True  -- O%3DC2/N%3DC%28%5CNc1n%28cnc12%29COC%28CO%29CO%29N could not be loaded.