ERROR opening https://cactus.nci.nih.gov/chemical/structure/CC1%3DC2C%28%3DCC%3DC1%29NC%3DC2C3%3DCCCNC3/file?format=sdf&get3d=True -- CC1%3DC2C%28%3DCC%3DC1%29NC%3DC2C3%3DCCCNC3 could not be loaded.