ERROR opening https://cactus.nci.nih.gov/chemical/structure/CC1%3DCCCC%28%3DC%29C2CC%28C2CC1%29%28C%29C/file?format=sdf&get3d=True  -- CC1%3DCCCC%28%3DC%29C2CC%28C2CC1%29%28C%29C could not be loaded.