ERROR opening https://cactus.nci.nih.gov/chemical/structure/CC1%3DC%28C2%28C1%28C%28%3DC2C%29C%29C%29C%29C/file?format=sdf&get3d=True -- CC1%3DC%28C2%28C1%28C%28%3DC2C%29C%29C%29C%29C could not be loaded.