ERROR opening https://cactus.nci.nih.gov/chemical/structure/CC1%3DCC2%3DC%28C%3DC1%29N3CCNC4C3%3DC2CCC4/file?format=sdf&get3d=True -- CC1%3DCC2%3DC%28C%3DC1%29N3CCNC4C3%3DC2CCC4 could not be loaded.