ERROR opening https://cactus.nci.nih.gov/chemical/structure/O%3DC2c1c%28O%29cccc1Cc3c2c%28O%29ccc3/file?format=sdf&get3d=True -- O%3DC2c1c%28O%29cccc1Cc3c2c%28O%29ccc3 could not be loaded.